Okay I have a 2000 Grand prix gt 3800 series II. Runs great but when you drive and press the pedal too far down it wont go. you cannot gun it. You have to baby it up to speed which really makes people behind me pissed. Ran 3 codes. PO131 PO134 and then multiple missfire. The Codes are with o2 sensors. 1 was already replaced. Please help me out guys it would be greatly appreciated. Thanks guys