a6killa

want to know which ones effect the cars performance the most? or do they all?

jseklund

The (2) O2 sensors before the cat give the computer information about the exhaust that allows it to adjust the air/fuel mixture and these can effect performance.

The (2) after the cat just tell the computer if the cat is doing its job for emissions purposes. These do not have any effect on purformance usually.

a6killa

thanks for the info mate.