[mtg6486]

ok so i went to island last night and tested my new turbo for the 1st time. i get about 4 passes down the track and after that my car started idleing a little rough. i gave it a rest and retried another run and the 1/4 mile times just started getting horrible. it ran crappy the whole way home and popped a code but it was for one of the oxygen sensors. i feel like it might be a missfire but im not seeing any codes to indicated one. my other thought is a vacume leak but on my first look didnt notice anything out of place. im going to check each plug & wire later today to rule those out but does anyone have any other ideas? the car is a 98 ta with an sts turbo kit running 7 lbs of boost