I have a 1998 Pontiac Grand Prix GT with 82,000 miles that i just finished a turbo project on. I have 1:9 Ratio Rockers and GTP injectors installed. The turbo i'm using is a Turbonetics T3/T4 Turbo running 7.5 - 8psi. I'm using a Greddy Type RS BOV and a Tial 38mm wastegate. I Have both the Z7 Turbo Crossover and Downpipe along with a catted TOG downpipe that is just straight pipe after the cat. I have a PCM from ZZ Performance that was tuned for the turbo and the GTP injectors. I did a FMIC setup also. I'm wondering why i'm having trouble with the car shutting off when the turbo spools uphill and i let off. This only happens when i'm going uphill, when driving on flat road it does not have a problem. My check engine light came on and is telling me that the upstream O2 sensor voltage is high. This is the first time I have turbo'd a car and i have no idea why this is happening. The car runs fine after i fire it back up once it dies uphill. I hope that someone will be able to help me out with this. Thanks