I recently had a set of pacesetter long tubes, and TSP true duals installed exactly a week ago today. As of last night my car started misfiring and running rough. I scanned it today and saw of course the o2 sensor codes (no cats) but code p0300 code random missfire poped up. I just need some reasons on why this code would pop up. I checked the mass air flow, coil packs, and found nothing lose. Has anyone else had this happen? I plan on taking the car to a tech on wednesday but would love to fix this myself if possible. If anyone has any ideas I would greatly appreciate the input.

Thanks
Chris

 

I had that code pop up and it was one of the injector connections had come off. Don't know if thats your prob but I would check all of those as well!

 

I will check...Thanks

 

fouled o2 sensor can cause problems too