Exhaust gas recirculation valves, or EGR valves, redirect hot exhaust gases back into your engine's intake manifold. EGR valves cut emissions and enhance engine efficiency; a failed EGR valve will result in a rough idle, loss of power, poor fuel economy, and a trouble code that illuminates the Check Engine light. The good news is that an EGR valve is simple to replace -- shop Advance Auto Parts for EGR valves from top brands like Carquest®, ACDelco® and Motorcraft®.