Well ever since winter hit this year my 2001 Grand Prix GTP has been having problems my alternator went out and I fixed it. I had a really bad exhaust leak and I got that fixed too. All common problems for an everyday driver over a 100k, but after that is when things started to get weird. During the time I had the exhaust leak I noticed that my car was Idleing weird, like going between 1000 and 2000 rpm, the problem persisted after I got the leak fixed, and I thought it must be an 02 sensor. Then I installed a Cold Air Intake today and the idleing problem ceased, when I went out onto the road to test it the Airbag light came on, my door locks clicked and my info screen, radio/cd player,all interior lights (except my gauge lights), completely went out. The issue continued sort of randomly, when I push the gas the lights go out, but when I push the brakes everything comes back on until I push the gas again. I had the battery checked, and a diagnostic run. the codes were PO742, PO420, basically 02 sensor, and torque converter locked on. I don't quite under stand how either of those things could cause this problem. maybe one of you guys could help me. thanx in advance.