Thanks for reading, I'm new to subarus, I just bought a 04 wrx two months ago and love it. The other night I was cruising around 50mph and my CEL came on. Next day I went to Autozone and had it scanned, P0420. (Catalyst System Efficiency Below Threshold (Bank 1). I then found out what this code could be by looking on google. I dropped off the car at a mechanic to have it checked out. It will be looked at on monday (8/17).
The current mods are:
K&N typhoon intake
TurboXS TBE with high flow cat
is the rear 02 sensor bad? it seems that after an aftermarket exhaust/cat and a good tune with these mods, it would be the sensor rather than a bad cat? Can i run with the sensor unplugged and just have the light reset? ANY help is appreciated!