I have a 2002 wrx and I have performance exhaust from the turbo back.It was on the car when i bought it and i dont know the brand.I think it may be m2.The problem i am having is the o2 sensor is bad and subaru says a stock one will not work.What can i get and where can I get a "performance" o2 sensor if such a thing is available.Any response would be helpful.

 

Huh?

You car has two O2 sensor. One is in exhaust manifold. The other is in your "mid" pipe just before your third catalytic converter (if you still have it).

The front O2 sensor is used by the ECU to maintain a near stoich A/F ratio during light throttle and cruising. This O2 sensor is very important to how the engine runs. If this O2 sensor was to go bad your engine would most likely run very poorly.

The rear O2 sensor sole purpose in life is to determine how well your catalytic converters are working (specifically your up-pipe and downpipe cats). It has no bearing on how much fuel is injected, so if it goes bad it will not affect how your car runs.

My suspicion is that we are talking about your rear O2 sensor. I imagine that your car was running fine, but your check engine light came on. So you took it to the dealer. The reason your check engine light came on is because you probably no longer have a cat in your down-pipe. Thus the ECU could see by reading the rear O2 sensor that the cats were not working properly (because they are sitting in someone's basement ). If this is the case the ODB-II code that the dealer read from your computer was a P0420. So you see your O2 sensor probably isn't even really bad. You can verify this with a multimeter to make sure it reads somewhere between .5 - 1.0 volts while you are driving around.

If my guess is correct, what you need is a small device that wires into the O2 sensor wires. It fools the ECU into thinking the cats are working.

Try here... http://www.ponyexpressperformance.co...liminator.html