Ive got a 99 ZR2 and I'm having issues with the o2 sensor. I've changed all 3 sensors with GM a new exhaust system with a new cat. and the light keeps coming on telling me bank one is bad. surely its not bad out of the box and the reason i question this is because the reason i changed them is because of that very reason the computer said bank one was bad. Is there something else that I'm missing? Also, is there something i can do to keep the A/C from turning off when the engine is under a load. I hate that!!!