I've had my race header installed for about 2 years now. At first I was just throwing the code for p0134 I believe for no cat. Then another one appeared about 6 months later for p0132 and p0132 pending for misfiring. I thought nothing of it as it still felt I wasn't losing power but my car would make this putting noise from the exhaust. Now after not driving my car for the whole winter I go and check my codes, and it said I was throwing about 6 or 7 codes! random misfiring with cyl 2 and 3 or something and the no cat is still there of course. I do have the little defouler trick but that works on and off but the misfiring is what scares me. When I drive it would sound like a wrx sometimes.

I've replaced the spark plugs and switched the coil packs around but the problems were still in the same cyls. Any ideas guys?

 

Okay, seriously this is the 6th thread I've seen on this. WHAT IS GOING ON WITH A2s??? Mine was doing the same thing. 10 codes but only 1 cyl was truely misfiring. My problem was an injector was causing cyl #4 to run rich. If you find your's to be the same, let me know, I've got extra injectors now.