Hi, I have a 2002 Spevc with a header. The downstream O2 Sensor has 2 spacers on it but still throws a code, and the exhaust smells fairly awful. It has been this way for a while - maybe 8000km or so, but I wasn't driving the car much and we don't have emissions tests in Vancouver any more, so...

I’ve recently learned that the precats on the Spec V’s can start failing and hurt the engine, so I want to get headers for my ‘06. But doing research I’m a little confused. I’m new to cars in general, so apologies if this is a total newb question. Where does the spacer go? Some of pictures show...

I discovered that my o2 sensor plug had fallen out one day so bought and installed a new one, this fixed the wrx boxer like engine sound coming out of the exhaust and temporarily turned off the check engine light. Unfortunately this only lasted for a couple miles of driving before the sound and...

I need help on how bypass the o2 sensors on my QR25DE I purchased an aftermarket header to delete the precat and now I keep getting ses codes for the 02 sensors. If anyone knows how to bypass them please help me out and tell me what I need to do.

i bought i megan header to replace the precat. I still have the second cat futher downstream. will i have to do the non fouler trick and would i put the non foulers on the first or second o2 sensor?

Greetings fellow sufferers. My lovely Primera with QR25 engine continues to behave like a spoiled kid - happy for a minute then grumpy and pissed off for no reason. It generally starts nicely from cold then deteriorates to being hard to start and having a lumpy idle when warm. I have already...