I have a 2000 grand am 3.4 L. It started shutting off on me while driving down the road. At first it would start back up shortly after. After a few times it didnt start back up so i replaced the fuel filter since i can hear the fuel pump turn on. It started back up and i got it home. Next day it shut off again but fired back up after a couple minutes. Next day it shut off and would not start back up. I towed it home and replaced the crank sensor. Fired up drove it around. Problem solved.....negative. Two days later i went to go to work and it would not start. I replaced the sensor again thinking maybe the one i got was faulty... still no go. I've tried leaving the key on because i heard about the security lock issues. Still nothing. Putting in on a tester shows a bad o2 sensor. Would that cause this problem? Any ideas would be great. I don't like to just throw money into something without an idea of what the problem may be.