well, to be honest the CRC did not work to pass the car, I had a clogged converter and the egr was not working right, but it did clean out all the gunk in the fuel system, the car runns awsome after you use it, if your car won't pass after you use it, have a teck look at your egr valve and catalytic converter, my car is old and if these parts are bad your car won't pass, your catalytic converter will get black powder coating on it in side. and there is nothing that will clean that off, but yes crc did bring the numbers of the test down by half, so it dose work, just not on a car with warn out parts,

I used this in a 2000 Honda Civic VP. I used the product as directed but it did not work. The Check Engine Light came on four hours after I turned it off. I then bought a more expensive competing product to clean the catalytic converter which worked -- the Check Engine light remained off and the car passed the emissions test.