Pontiac Repair: 2002 Grand Prix Stalls, crank shaft position sensor, grand prix gtp

Question
I have a 2002 Pontiac Grand Prix GTP 3.8 with 140,000 miles.  I stopped at a stop light and it stalled and started right back up again without hesitation.  About a year ago the diagnostic said I needed O2 sensors.  Since they haven't been replaced yet could this be my problem?  Or am I looking at a bigger issue?

Answer
Hi Jennifer:

An O2 sensor will not cause a stall condition. when it stalled was it while you were stopped or while you were slowing down comming to a stop? when it stalled did it spit sputter and chug then die or was it like someone turned off the key? It makes a difference in which way to look at this. It only did it one time? I'm thinking it's either a idle control motor/dirty throttle plate or a crank shaft position sensor.