I had my test pipe on my car for about 2 months and when I installed it i used the check engine light trick with the 2 spark plug anti-foulers on the rear o2 sensor, i never got a check engine light or had any problem, the car ran perfectly fine.

Recently my car started to back far like crazy... any time a produced more than 5 psi above 3000 rpms there would be constant back fires.

I have a friend with a Vag who ran it on my car and it told me that the rear o2 sensor was not giving out any signal, I have never changed my o2 sensors and i have about 73,000 miles. The vag also read that i had misfires in 2 of my cylinders but that there were 2 different types of misfires and mine was the not so bad one.lol.

Heres what Ive done:

Replaced n75 valve , replaced MAF, ordered 02 sensor and awaiting the arrival.

What Im wondering if that by having a faulty 02 sensor would it cause your car to back fire like mine has?

If I replace the 02 sensor and the backfires still continue does anyone have any other suggestions? I like my testpipe and would perfer to keep it if possible.

 

Clear the codes, replace the spark plugs drive for a day and retest. If you have a misfire gas could be igniting in you exhaust. I wouldn't worry about o2 sensor, is it disable for the test pipe with the chip? If you o2 sensor is bad and not disabled it would turn on the cel.

 

well.... i have a giac chip so no the chip isnt programed to turn the test pipe off.. I never had a CEL until this started to happen and now i do have a cel. I did change my spark plugs, it was the first thing i did and nothing changed

 

u only put nonfoulers on the rear? does it send false readings or what? im trying to decide if i should live with the CEL till i get the APR chip

 

your rear o2 sensor has nothing to do with the cars performance or fuction, it only monitors if your catalyst is functioning

 

does it backfire as your accecelerating or when your off the gas? do you have an after market exhaust? is it resonated? I have a testpipe and it backfires only on decelaration but its normal becuse I have a non resonated turbo back exhaust