Hi guys.
since I bought my grand prix I keep having my engine light on related to the o2 sensors.
I replaced both the upstream and downstream sensors and I have also erased the errors with the tech 2 plus u checked the values of the sensors with the tech 2. They pretty much seem to match. The check engine light keeps coming up tho.
On my exhaust, after the cat (un the middle section) I got rid of the silencer and I put a straight pipe. Could it be the reason why it keeps giving me the error? Could it be a faulty pcm? Or maybe I need a new cat?
I understand I'm not giving so many useful info but I'm hoping in a common problem.
Thanks
