alright first off my car has been fireering the service engine soon light when it does this I am usualy running it hard. Now before the SES light comes on tne car will sound like it is miss fireering between 4500 and red line it will sometimes even hit the rev limmiter next about 5 to 10 min latter the SES light shows up and the missing and over all ****y running stops so I took it to a buddy he checked the computer and said it was a bad opti or mabee just a bad O2 so I changed the O2 the problem stoped so far (only 36 hours) but it has also ran good for up to a week before the new O2 so my question is what do you think Bad Opti or the bad O2.

Thank

 

what was the code your buddy pulled from the car?