Ok i have a 97 GSR and getting rid of my stock exhuast. On passed hondas I know from high flow cats and test pipes that the check engine light comes on because of the o2 sensor. I have used O2 depletion kits and the light turns off. But i dont think that is good for the car not being able to read the air fuel mixture. What could i do on useing an aftermarket cat ?? Or on check engin light ??

Thanks Nick

 

If you have a functional cat, the CEL won't come on from the 2nd O2 sensor.