2003 Toyota 4Runner Spark Plugs

Your 2003 Toyota 4Runner might be the best vehicle you’ve ever owned. Or you may just be struggling to keep it highway-approved. No matter the situation, Advance Auto Parts has the Spark Plugs you desperately need.

We currently carry 49 Spark Plugs to choose from for your 2003 Toyota 4Runner, and our inventory prices range from as little as $2.29 up to $16.99.

On top of low prices, Advance Auto Parts offers 6 different trusted brands of Spark Plugs for the 2003 Toyota 4Runner. We only sell parts from trusted brands like Autolite so that you can find quality parts you can count on.

Don’t take our word for it – check out customer ratings and reviews to buy with confidence. We have 6,885 reviews on our Spark Plugs for the 2003 Toyota 4Runner from previous customers.

Have parts delivered straight to your home, or find the nearest Advance Auto Parts store to check out our Spark Plugs stock in-person!

Spark Plugs for Your 2003 Toyota 4Runner

DENSO – Iridium Long-Life Spark Plug: OE Performance, last 100K+ Miles, SK20R11 (Part No.3297)

Iridium Long-Life Spark Plug:  OE Performance, last 100K+ Miles, SK20R11

from

$10.79
Manufactured to the strictest OE performance, durability and emissions standards.

Product Features:
  • Latest OE technology with DENSO’s patented Iridium Alloy (90% Ir) and fine wire center electrode
  • Platinum ground electrode for extended life
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Sustained spark performance over 100,000 miles
  • Lasts up to three times as long as conventional plugs
  • Endures extreme temperatures greater than 4,000 degrees F associated with high-performance ignition and special fuel systems
  • Iridium Long Life
  • Enhanced Engine Performance: Enjoy more horsepower, faster and easier starts, and fewer misfires under heavy loads, thanks to the advanced properties of DENSO’s Iridium alloy.
  • Fuel Efficiency: The DENSO Iridium Long Life plug helps in better conservation of fuel, making it an economical choice for long-term use.
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DENSO – Iridium Long-Life Spark Plug: OE Performance, last 100K+ Miles, SK20HR11 (Part No.3421)

Iridium Long-Life Spark Plug:  OE Performance, last 100K+ Miles, SK20HR11

from

$11.49
Manufactured to the strictest OE performance, durability and emissions standards.

Product Features:
  • Latest OE technology with DENSO’s patented Iridium Alloy (90% Ir) and fine wire center electrode
  • Platinum ground electrode for extended life
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Sustained spark performance over 100,000 miles
  • Lasts up to three times as long as conventional plugs
  • Endures extreme temperatures greater than 4,000 degrees F associated with high-performance ignition and special fuel systems
  • Iridium Long Life
  • Enhanced Engine Performance: Enjoy more horsepower, faster and easier starts, and fewer misfires under heavy loads, thanks to the advanced properties of DENSO’s Iridium alloy.
  • Fuel Efficiency: Experience better conservation of fuel at all times, contributing to overall vehicle efficiency and cost savings.
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NGK – G-Power Spark Plug: Single Platinum Tip Design, BKR6EGP (Part No.7092)

G-Power Spark Plug: Single Platinum Tip Design, BKR6EGP

from

$6.29
NGK G-Power Platinum spark plugs are the best single platinum spark plugs at an economical price. G-Power plugs feature a fine wire platinum center electrode and a trapezoidal cut ground electrode that offers increased durability, improved fuel efficiency

Product Features:
  • SINGLE PLATINUM TIP: Fine wire 0.6 millimeter platinum tip center electrode ensures improved durability and a consistently stable spark
  • PLATINUM ALLOY: G-Power platinum provides exceptional value with increased performance and longer service intervals than factory nickel plugs
  • TRAPEZOIDAL CUT GROUND ELECTRODE: Reduces quenching design produces improved ignitability and performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • RECOMMENDED USAGE: Lower cost alternative to double precious metal spark plugs or as an upgrade to OE nickel alloy spark plugs
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NGK – Iridium IX Spark Plug: Single Iridium Fine Wire, BKR6EIX-11 (Part No.3764)

Iridium IX Spark Plug: Single Iridium Fine Wire, BKR6EIX-11

from

$11.99
NGK Iridium IX spark plugs are specifically designed for the performance enthusiast. Iridium IX provides outstanding acceleration, high fuel efficiency and durability. NGK Iridium IX plugs offer extreme ignitability and exceptional anti-fouling. Tapered c

Product Features:
  • SINGLE IRIDIUM TIP: Fine wire 0.6 millimeter iridium tip center electrode ensures high durability and a consistently stable spark
  • IRIDIUM ALLOY CENTER ELECTRODE: Iridium’s density (6x that of platinum) and extremely high melting point is perfect for modern high efficiency engines
  • TAPERED CUT GROUND ELECTRODE: Reduced quenching design produces outstanding ignitability, improved acceleration, fuel efficiency and durability
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Modified or high performance applications, or as an upgrade to OE nickel alloy spark plugs
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NGK – OE Series V-Power Nickel Spark Plug: V-Groove Tip Design, BKR6E-11 (Part No.2756)

OE Series V-Power Nickel Spark Plug: V-Groove Tip Design, BKR6E-11

from

$4.99
NGK V-Power spark plugs offer reliable performance and improved ignitability over standard nickel plugs. Engineered specifically for OE applications, the special V-cut nickel alloy center electrode and concave ground electrode of NGK’s V-Power spark plug

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction nickel alloy center electrode with V-groove provides consistent performance
  • RECOMMENDED USAGE: Best for vehicles with OE nickel alloy plugs, not recommended on vehicles with factory precious metal plugs
  • NGK’s OE CERAMIC TECHNOLOGY: High grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
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NGK – OE Series Laser Iridium Spark Plug: Fine Wire Tip Design, IFR6T11 (Part No.4589)

OE Series Laser Iridium Spark Plug: Fine Wire Tip Design, IFR6T11

from

$12.99
Often specified as original equipment, NGK Laser Iridium spark plugs are the best combination of performance and longevity. Iridium tip is six (6) times harder than platinum providing the strongest ignitability and the longest life possible. Most Laser Iridium spark plugs feature a platinum pad on the ground electrode for even wear in DIS ignition systems. OE engineered for specific vehicle applications.

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction fine wire iridium alloy center electrode provides consistent performance
  • IRIDIUM ALLOY CENTER ELECTRODE: Iridium’s density (6x that of platinum) and extremely high melting point is perfect for modern high efficiency engines
  • PLATINUM TIP GROUND ELECTRODE: Unless OE specified, platinum protection at the ground electrode provides excellent ignitability and service life
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Best for vehicles with OE fine wire iridium alloy plugs
  • High-Grade Pure Alumina Ceramic: Prevents overheating and ensures reliable starts, enhancing overall engine performance.
  • Platinum Pad on Ground Electrode: Ensures even wear in distributorless ignition systems, contributing to consistent performance.
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NGK – OE Series Standard Nickel Spark Plug: Conventional Tip Design, BKR6ES-11 (Part No.5553)

OE Series Standard Nickel Spark Plug: Conventional Tip Design, BKR6ES-11

from

$4.99
NGK Standard spark plugs (in the iconic NGK ‘yellow box’ packaging) are a proven OE cornerstone and technology customers have relied on for decades. Engineered specifically for OE applications, NGK Standard spark plugs provide OE quality nickel alloy reliable performance and design. NGK’s legendary high grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance, while triple gasket sealing prevents combustion gas leakage. Solid 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges. Trivalent metal plating ensures superior anti-corrosion and anti-seizing properties.

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction nickel alloy center electrode provides consistent performance
  • RECOMMENDED USAGE: Best for vehicles with OE nickel alloy plugs, not recommended on vehicles with factory precious metal plugs
  • NGK’s OE CERAMIC TECHNOLOGY: High grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • Triple Gasket Sealing: Prevents combustion gas leakage, ensuring efficient engine performance.
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NGK – OE Series V-Power Nickel Spark Plug: V-Groove Tip Design, LFR6C-11 (Part No.7787)

OE Series V-Power Nickel Spark Plug: V-Groove Tip Design, LFR6C-11

from

$9.99
NGK V-Power spark plugs offer reliable performance and improved ignitability over standard nickel plugs. Engineered specifically for OE applications, the special V-cut nickel alloy center electrode and concave ground electrode of NGK’s V-Power spark plug increases ignitability providing quicker starts and smoother idle. NGK’s legendary high grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance. Trivalent metal plating ensures superior anti-corrosion and anti-seizing properties.

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction nickel alloy center electrode with V-groove provides consistent performance
  • RECOMMENDED USAGE: Best for vehicles with OE nickel alloy plugs, not recommended on vehicles with factory precious metal plugs
  • NGK’s OE CERAMIC TECHNOLOGY: High grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • Enhanced Ignitability: The V-cut nickel alloy center electrode and concave ground electrode design of NGK V-Power spark plugs provide quicker starts and smoother idle.
  • OE Application Specific: Engineered specifically for Original Equipment (OE) applications, ensuring compatibility and performance with your vehicle.
  • V-Groove Tip Design: The unique V-groove tip design enhances ignitability and overall engine performance.
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DENSO – Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, last 100K+ Miles, IKH20TT (Part No.4704)

Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, last 100K+ Miles, IKH20TT

from

$10.99
Durability of an OE style plug combined with Power & Torque of high performance.

Product Features:
  • 0.4mm Iridium Center Electrode: World’s Smallest Diameter that maximizes firing potential
  • 0.7mm Needle Tip Ground Electrode: Promotes higher spark energy and less heat quenching
  • DENSO Patented Optimized Iridium-Rhodium Alloy Formula: Highest concentration of Iridium vs. competitors for greater durability
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Durability of an OE style plug combined with Power & Torque of high performance.
  • Withstands temperatures greater than 4000° Fahrenheit
  • Iridium TT
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DENSO – Iridium Power Spark Plug: Maximum Spark Energy, 0.4mm Iridium Tip, IK20 (Part No.5304)

Iridium Power Spark Plug: Maximum Spark Energy, 0.4mm Iridium Tip, IK20

from

$11.79
Increased performance with World’s smallest Iridium Center Eletrode (0.4mm).

Product Features:
  • World’s smallest Iridium Center Electrode (0.4mm) for improved spark for maximum combustion
  • Patented 360-degree laser welding assembly process
  • U-groove and taper cut ground electrode to maximize flame propagation.
  • Withstands temperatures greater than 4000° Fahrenheit
  • Burnished nickel plating for high temperature endurance and superior corrosion resistance
  • Wide range of part numbers for thousands of applications, including classic and collector cars
  • Iridium Power
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Champion – Double Platinum & Power Spark Plug Exceptional Perf OE Replacement RC10PLPB4 (Part No.7436)

Double Platinum & Power Spark Plug Exceptional Perf OE Replacement RC10PLPB4

from

$9.49
Champion® Double Platinum Power¿ spark plugs deliver more powerful performance. Featuring exclusive Heat-Active¿ alloy, platinum fine wire center electrode and platinum pad ground electrode provide maximum life and sharper spark focus.

Product Features:
  • Double Platinum Power – Premium Spark Plug. More Powerful Performance.
  • Platinum center and ground electrode for greater wear resistance
  • Maintains stable operating temperature under all engine loads
  • Fine-wire center electrode for greater ignitability
  • V-trimmed ground electrode promotes sharper spark focus
  • Heat-Active┐ alloy allows electrodes to reach optimal temperature
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NGK – Ruthenium HX High Ignitability Spark Plug: DFE Tip Design, FR6AHX-S (Part No.94279)

Ruthenium HX High Ignitability Spark Plug: DFE Tip Design, FR6AHX-S

from

$15.99
NGK Ruthenium HX High Ignitability spark plugs are the best in class plug for todays modern vehicles. Patented Ruthenium technology offers the most advance tip technology and delivers the highest performance and life expectancy. Created from advanced OE t

Product Features:
  • HIGH IGNITABILITY DOUBLE FINE ELECTRODE DESIGN: Combines 0.6 millimeter ruthenium center with opposed fine wire platinum ground electrode
  • RUTHENIUM ALLOY CENTER ELECTRODE: NGK’s patented ruthenium technology produces maximum performance, ignitability & durability at high temperatures
  • PLATINUM PIN TYPE GROUND ELECTRODE: Provides more complete fuel burn, quicker throttle response, smoother idle and better cold starts
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Modern vehicles using OE DFE type spark plugs or for those seeking an aftermarket plug with the latest OE technology
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Champion – Platinum Power Spark Plug: Powerful Perfromance, OE Replacement, RC12PMC4 (Part No.3318)

Platinum Power Spark Plug: Powerful Perfromance, OE Replacement, RC12PMC4

from

$5.29
Champion® Platinum Power™ spark plugs deliver powerful performance. Made from exclusive Heat-Active™ alloy, a fine-wire center electrode and V-trimmed ground electrode provides sharp spark focus.

Product Features:
  • Platinum Power- Premium Spark Plug. Powerful Performance.
  • Platinum center electrode for long life
  • Fine-wire center electrode for greater ignitability
  • V-trimmed ground electrode promotes sharper spark focus
  • Heat-Active™ alloy allows electrodes to reach optimal temperature
  • Platinum tipped center wire resists wear and helps to maintain proper gap spec over life of the plug
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Autolite – Racing Resistor Spark Plug: Enables Performance, Handles Intense Conditions (Part No.AR3923)

Racing Resistor Spark Plug: Enables Performance, Handles Intense Conditions

from

$4.99
The ground electrode is cut-back from the center electrode to provide a gap. The face of the ground electrode is concave to provide a constant gap to the center electrode. This plug is designed use in all aftermarket cylinder heads used in different types of racing venues including oval and road racing.

Product Features:
  • Opens spark face for better ignitability of flame kernel
  • Retains less heat, transfers heat to shell faster – reduces risk of pre-ignition
  • Dyno testing has shown proven power gains
  • Cut-back ground electrode evolved from practice of grinding back the side electrode
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ACDelco – Double Platinum Spark Plug (Part No.41-801)

Double Platinum Spark Plug

from

$9.79
ACDelco Gold (Professional) Double Platinum Spark Plug are a high quality alternative to Original Equipment (OE) parts. With a copper core and double platinum pads on the center electrode, these plugs are designed to deliver long-lasting performance. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco Gold (Professional) parts are manufactured to meet your expectations for fit, form, and function, making them a smart choice for General Motors vehicles, as well as most makes and models, including special applications. These high-quality parts are backed by General Motors. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.

Product Features:
  • One-piece, fired-in suppressor seal blends three glass types for a gas-tight seal that helps reduce radio frequency and engine interference, regulate spark plug energy, and protect against compression pressures for long life
  • Double platinum point pad on center and ground electrode offer excellent durability and consistent voltage demands to help reduce wear on ignition system
  • Pure copper core results in cooler electrode temperature for maximized durability and fouling resistance
  • Some ACDelco Gold parts may have formerly appeared as ACDelco Professional
  • Premium aftermarket replacement part
  • Manufactured to meet specifications for fit, form, and function for General Motors vehicles as well as most makes and models
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DENSO – Double Platinum Spark Plug: OE Performance, lasts 60K+ Miles, PK20R11 (Part No.3128)

Double Platinum Spark Plug:  OE Performance, lasts 60K+ Miles, PK20R11

from

$9.79
Manufactured to the strictest OE performance, durability and emissions standards.

Product Features:
  • OE grade platinum on both center and ground electrods
  • Premium shell construction with machine-rolled threads
  • Superior thermal conductivity
  • Sustained spark performance over 60,000 miles
  • Reduced secondary required voltage, increased ignition efficiency
  • Satisfied customers, reduced shop comebacks
  • Double Platinum
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Autolite – Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration (Part No.5325)

Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration

from

$3.49
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Guaranteed to deliver quick starts, good fuel economy and smooth acceleration, Autolite Copper Core spark plugs are designed to meet or exceed OES design requirements. Consider upgrading to Autolite Platinum, Double Platinum or Iridium XP plugs for improved engine performance. Copper core plugs are the industry standard.

Product Features:
  • Copper-glass seal bonds insulator, terminal post center electrode together; assures full required voltage at spark gap; gas-tight seal (100% leak proof)
  • Multi-rib insulator reduces danger of “flash-over”
  • One-piece terminal post adds strength
  • Resistor reduces radio frequency interference (RFI) and electrode erosion
  • Quick Starts: Autolite Copper Core spark plugs are engineered to ensure your engine starts quickly and reliably every time.
  • Good Fuel Economy: Designed to optimize fuel efficiency, these spark plugs help you get the most out of every gallon of gas.
  • Smooth Acceleration: Experience seamless and smooth acceleration with Autolite Copper Core spark plugs, enhancing your driving experience.
  • OES Design Compliance: These spark plugs are crafted to meet or exceed Original Equipment Service (OES) design requirements, ensuring high-quality performance.
  • Industry Standard: Autolite Copper Core spark plugs are recognized as the industry standard, backed by over 100 years of engineering expertise and the sale of over 11 billion plugs.
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NGK – OE Series Laser Platinum Spark Plug: Fine Wire Tip Design, PLFR6A-11 (Part No.7654)

OE Series Laser Platinum Spark Plug: Fine Wire Tip Design, PLFR6A-11

from

$16.99
NGK Laser Platinum spark plugs provide high ignitability and longer service life compared to conventional nickel spark plugs. Laser Platinum plugs are tested to the highest standards to ensure quality and durability. Engineered specifically for OE applications. Laser platinum plugs provide stable idling, superior anti-fouling, improved fuel efficiency and lower emissions. High-grade pure alumina ceramic and 98% pure copper core prevents spark plug from overheating and provides reliable starts. Most Laser Platinum spark plugs feature a platinum pad on the ground electrode for even wear in distributorless ignition systems.

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction fine wire platinum alloy center electrode provides consistent performance
  • PLATINUM ALLOY CENTER ELECTRODE: Longer wearing and higher temperature resistance compared to traditional nickel spark plugs
  • PLATINUM TIP GROUND ELECTRODE: Unless OE specified, platinum protection at the ground electrode provides excellent ignitability and service life
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Best for vehicles with OE fine wire platinum alloy plugs
  • Enhanced Fuel Efficiency and Lower Emissions: These spark plugs contribute to improved fuel efficiency and reduced emissions, making them an eco-friendly choice.
  • Superior Anti-Fouling and Stable Idling: The advanced design provides stable idling and superior resistance to fouling, ensuring consistent engine performance.
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Champion – Double Platinum & Power Spark Plug Exceptional Perf OE Replacement REC10PYPB4 (Part No.7975)

Double Platinum & Power Spark Plug Exceptional Perf OE Replacement REC10PYPB4

from

$7.99
Champion® Double Platinum Power¿ spark plugs deliver more powerful performance. Featuring exclusive Heat-Active¿ alloy, platinum fine wire center electrode and platinum pad ground electrode provide maximum life and sharper spark focus.

Product Features:
  • Double Platinum Power – Premium Spark Plug. More Powerful Performance.
  • Platinum center and ground electrode for greater wear resistance
  • Maintains stable operating temperature under all engine loads
  • Fine-wire center electrode for greater ignitability
  • V-trimmed ground electrode promotes sharper spark focus
  • Heat-Active┐ alloy allows electrodes to reach optimal temperature
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DENSO – Iridium Long Life Spark Plug (Part No.F1000114522ND)

Iridium Long Life Spark Plug

from

$12.32
The DENSO Iridium Long Life spark plug was specifically designed for long service life and consistent performance in the latest, most advanced production cars DENSO’s patented iridium alloy is more durable than even platinum, allowing the center electrode to be shrunk to only 0.7mm in diameter. This produces a dramatic improvement in ignitability and spark plug life. Closely related to platinum and exhibiting even tougher qualities, the rare metal iridium is an ideal material for spark plugs. A fine-wire, 0.7mm iridium center electrode is 360-degree laser welded in place using an exclusive DENSO process, and then matched to a platinum ground electrode. This pair of precision-formed, premium-metal electrodes dramatically extends the plug’s useful life.

Product Features:
  • Fine-wire iridium center electrode
  • Platinum ground electrode
  • 360 degree laser-welded spark tip
  • Sustained spark performance over 100,000 miles
  • Withstands higher pressures and temperatures
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Autolite Iridium – Iridium XP Finewire Spark Plug: Improved Durability, More Focused Ignition (Part No.XP5325)

Iridium XP Finewire Spark Plug: Improved Durability, More Focused Ignition

from

$9.99
Our best spark plug! Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, the Autolite Iridium XP spark plugs feature an iridium-enhanced 0.6mm finewire design and patented platinum sidewire technology to provide better overall durability and a more focused ignition for enhanced ignitability and performance. Features double Iridium-enhanced alloy technology center electrode for improved durability and wear resistance.

Product Features:
  • 0.6 mm finewire design improves ignitability
  • Patented V-trimmed platinum sidewire technology resists wear
  • OE equivalent design is engineered for every engine
  • Designed for better overall durability with virtually no gap erosion
  • Double Iridium-Enhanced Alloy Technology Center Electrode: Offers improved durability and wear resistance for a longer-lasting spark plug.
  • Designed and Engineered in the USA: Reflects over 100 years of Autolite’s engineering experience and expertise.
  • Gasket Seat Type: Ensures a secure and proper fit for optimal performance.
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Autolite – Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration (Part No.AP5325)

Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration

from

$4.79
With over 100 years of engineering expertise and over 11 billion plugs sold, Autolite Platinum spark plugs are designed and engineered in the USA to deliver exceptional performance. Featuring a high nickel alloy side electrode that maintains a precise gap and a full platinum tip that ensures virtually no gap erosion, these spark plugs offer long-lasting durability. The necked-down center electrode fires quicker and cleaner with less voltage, resulting in easier starts, quicker acceleration, and improved fuel economy compared to standard plugs.

Product Features:
  • High nickel alloy side electrode maintains precise gap
  • Full platinum tip assures virtually no gap erosion for long life
  • Necked-down center electrode fires quicker, cleaner with less voltage for easier starts, quicker acceleration and improved fuel economy (as compared to standard plugs)
  • Improved Fuel Economy: Designed to enhance fuel efficiency compared to standard plugs.
  • Engineered in the USA: Backed by over 100 years of engineering expertise and over 11 billion plugs sold.
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DENSO – Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, last 100K+ Miles, IK20TT (Part No.4702)

Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, last 100K+ Miles, IK20TT

from

$10.99
Durability of an OE style plug combined with Power & Torque of high performance.

Product Features:
  • 0.4mm Iridium Center Electrode: World’s Smallest Diameter that maximizes firing potential
  • 0.7mm Needle Tip Ground Electrode: Promotes higher spark energy and less heat quenching
  • DENSO Patented Optimized Iridium-Rhodium Alloy Formula: Highest concentration of Iridium vs. competitors for greater durability
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Durability of an OE style plug combined with Power & Torque of high performance.
  • Withstands temperatures greater than 4000┬░ Fahrenheit
  • Iridium TT
  • Ultimate Endurance and Power: The DENSO Iridium TT Spark Plug features a 0.7mm Iridium Tip, ensuring over 100,000 miles of uncompromised performance.
  • Advanced Twin-Tip Technology: Developed from Original Equipment Specification Super Ignition Plug (SIP) design, combining a Fine Wire Iridium Center Electrode with a Needle Tip Platinum Ground Electrode.
  • Enhanced Fuel Economy and Lower Emissions: Drive around the Earth over 4 times with improved fuel efficiency and reduced emissions.
  • Premium Materials: Features an Iridium Center Electrode Tip and a Flat Seat Type for optimal performance and durability.
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Autolite Iridium – Iridium XP Finewire Spark Plug: Improved Durability, More Focused Ignition (Part No.XP3923)

Iridium XP Finewire Spark Plug: Improved Durability, More Focused Ignition

from

$9.99
Our best spark plug! Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, the Autolite Iridium XP spark plugs feature an iridium-enhanced 0.6mm finewire design and patented platinum sidewire technology to provide better overall durability and a more focused ignition for enhanced ignitability and performance. Features double Iridium-enhanced alloy technology center electrode for improved durability and wear resistance.

Product Features:
  • 0.6 mm finewire design improves ignitability
  • Patented V-trimmed platinum sidewire technology resists wear
  • OE equivalent design is engineered for every engine
  • Designed for better overall durability with virtually no gap erosion
  • Double Iridium-Enhanced Alloy Technology Center Electrode: Offers improved durability and wear resistance for a longer-lasting spark plug.
  • Designed and Engineered in the USA: Reflects over 100 years of Autolite’s engineering experience and expertise.
  • Gasket Seat Type: Ensures a secure and proper fit for optimal performance.
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Autolite – Double Platinum Spark Plug: Platinum Firing, Superior Durability, Longer Life (Part No.APP5325)

Double Platinum Spark Plug: Platinum Firing, Superior Durability, Longer Life

from

$6.79
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Double Platinum spark plugs feature platinum-to-platinum firing which virtually eliminates gap erosion, reduces misfires and increases durability of the plug. Consider upgrading to Autolite Iridium XP spark plugs for increased performance.

Product Features:
  • Works to optimize engine performance for a longer life and improved fuel economy
  • OE design
  • Full-platinum tips; platinum on both the center and side electrodes to promote reduced gap wear
  • Platinum ball welding process provides a consistent point of contact for enhanced adhesion
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Autolite – Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration (Part No.AP3923)

Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration

from

$4.79
With over 100 years of engineering expertise and more than 11 billion plugs sold, Autolite Platinum spark plugs are designed and engineered in the USA to deliver exceptional performance. Featuring a high nickel alloy side electrode that maintains a precise gap and a full platinum tip that ensures virtually no gap erosion, these spark plugs offer long-lasting durability. The necked-down center electrode fires quicker and cleaner with less voltage, resulting in easier starts, quicker acceleration, and improved fuel economy compared to standard plugs.

Product Features:
  • High nickel alloy side electrode maintains precise gap
  • Full platinum tip assures virtually no gap erosion for long life
  • Necked-down center electrode fires quicker, cleaner with less voltage for easier starts, quicker acceleration and improved fuel economy (as compared to standard plugs)
  • Exceptional Performance: Designed and engineered in the USA, Autolite Platinum Spark Plugs deliver superior performance with over 100 years of engineering expertise and more than 11 billion plugs sold.
  • Gasket Seat Type: Equipped with a gasket seat type, these spark plugs provide a secure and effective seal for optimal engine performance.
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NGK – Iridium IX Spark Plug: Single Iridium Fine Wire, LFR6AIX-11 (Part No.6619)

Iridium IX Spark Plug: Single Iridium Fine Wire, LFR6AIX-11

from

$12.99
NGK Iridium IX spark plugs are specifically designed for the performance enthusiast. Iridium IX provides outstanding acceleration, high fuel efficiency and durability. NGK Iridium IX plugs offer extreme ignitability and exceptional anti-fouling. Tapered c

Product Features:
  • SINGLE IRIDIUM TIP: Fine wire 0.6 millimeter iridium tip center electrode ensures high durability and a consistently stable spark
  • IRIDIUM ALLOY CENTER ELECTRODE: Iridium’s density (6x that of platinum) and extremely high melting point is perfect for modern high efficiency engines
  • TAPERED CUT GROUND ELECTRODE: Reduced quenching design produces outstanding ignitability, improved acceleration, fuel efficiency and durability
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • RECOMMENDED USAGE: Modified or high performance applications, or as an upgrade to OE nickel alloy spark plugs
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E3 – DiamondFIRE Automotive Spark Plug: More Power, Saves Gas (Part No.E3.68)

DiamondFIRE Automotive Spark Plug: More Power, Saves Gas

from

$6.99
The Spark Plugs are the product of years of fundamental research in the combustion field. The unique patented electrode configuration of these new The spark plugs increases the amount of combustion pressure created during each power stroke of an engine, which results in a marked increase in power output, fuel economy, and reduced emissions in all gasoline engines. E3.68 is a 14mm, 1.000 reach plug with a gasket seat. It fits a wide variety of late model applications, especially Hemi applications. E3.68 is widely stocked in automotive retail stores. The automotive plugs have three legs securing the Diamond FIRE electrode to the shell. This allows for excellent heat transfer, and helps to create more turbulence in the cylinder. The patented Diamond FIRE side wire is proven to increase power, reduce fuel consumption and improve hydrocarbon emissions in long-term use.

Product Features:
  • E3’s Diamond Fire edge to edge ground electrode provides maximum performance with increased efficiency and a faster more complete burn
  • Smoother Acceleration & Idle – The faster flame initiated by the The spark plug results in a more complete burn of the ingested fuel charge. More pressure is created against the piston more fuel is put to work
  • Energy – Power output improved up to 6% on average in the typical operating ranges. Results will vary.
  • Efficiency – The “diamond shaped” side wire electrode projects the combustion spark in a way that more quickly ignites the air/fuel mixture, thereby creating a significantly faster and larger flame kernel. The result is that more fuel is put to work durin
  • E3’s patented Diamond Fire Technology provides a cleaner burning combustion, which translates into fuel savings and reduced engine carbon deposits
  • The Spark Plugs are pre-gapped at the factory and cannot be adjusted.
  • Wide Compatibility: E3.68 spark plugs are 14mm with a 1.000 reach and a gasket seat, fitting a wide variety of late model applications, especially Hemi engines.
  • Enhanced Heat Transfer: The three legs securing the Diamond FIRE electrode to the shell ensure excellent heat transfer and create more turbulence in the cylinder for better combustion.
  • Widely Available: E3.68 spark plugs are widely stocked in automotive retail stores, making them easily accessible for consumers.
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FAQs for 2003 Toyota 4Runner Spark Plugs

What are the most popular Spark Plugs for the 2003 Toyota 4Runner?

With 6 brands you can trust, our most popular Spark Plugs for the 2003 Toyota 4Runner parts are:

What are the best aftermarket Spark Plugs for the 2003 Toyota 4Runner?

See what past customers had to say about our highest-rated Spark Plugs for the 2003 Toyota 4Runner:
Iridium Long-Life Spark Plug:  OE Performance, last 100K+ Miles, SK20R11
from $10.79
(233)
Iridium Long-Life Spark Plug: OE Performance, last 100K+ Miles, SK20R11
“good service and quality parts”
G-Power Spark Plug: Single Platinum Tip Design, BKR6EGP
from $6.29
(152)
G-Power Spark Plug: Single Platinum Tip Design, BKR6EGP
“I bought these as a upgrade dor my 91 Miata. Direct drop in and it definitely starts and idles better now.”
Iridium IX Spark Plug: Single Iridium Fine Wire, BKR6EIX-11
from $11.99
(113)
Iridium IX Spark Plug: Single Iridium Fine Wire, BKR6EIX-11
“Great plugs, great price!”