Pontiac Repair: 1998 Monte Carlo, crank shaft position sensor, grasping at straws

Question
QUESTION: Hi Todd, Help, drove on the highway for an hour, exited and pulled up to the first stop light. While waiting on the light the car just stalled out. It started right back up but would not idle and stalled again. Restarted and stalled 4 or 5 times before I just managed to creep it into an adjacent parking lot. It would start but would not idle for more than a minute or two at the most before stalling out. Had it towed to my mechanic but after sitting all night it started right up and idled just fine. He is not able to pin point anything specific as the problem and cannot get it to act up. He seems to be leaning toward the ignition module but is not sure. By the way, this exact same thing happened 3 months ago when I was out of town with no problem found and plugs,wires,tuneup was done. Any ideas what might be happening?  Thanks, Dave.

ANSWER: Hi Dave:

what engine is in this car? It can be a lot of different things.. did you have to keep your foot on the gas to keep it running? when it was running was it misfiring? does the car have a gauges package if so did the tachometer jump all over or was it steady? were any dtc's stored in the engine computer? If so that is a clue to where to start looking. Any service engine soon lmap on steady or flashing? And ignition module is grasping at straws and a guess but not out of the question.

---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick resonse Todd. 3.1, 6 cylinder. Foot on the gas pedal or flutter stepping the pedal did absolutly nothing to keep it running. Did not really notice the tach but I'm pretty sure it was jumping around. The only thing the computer showed was misfiring. Any suggestions? Thanks again.

Answer
You could have a crank shaft position sensor that's acting up when hot or the wiring to the sensor may be bad "high resistance" I have seen engine data sensors go bad when hot and all the other ones they are paired up with go down like a MAP sensor going bad may take out the TPS or an a/c pressure sensor take out a TPS I dopn't mean make it go bad but the sensor shorts out and the other sensors act up due to the one going bad. Rare but have seen it happen. It could be an idle control valve that is bad but that will not make it misfire. It's off that it hasn't set any other codes. Does this car have a lot of miles on it? do you live in the "rust belt" You could have a bad ground wire connectionfor the engine computer or a bad connection at the battery did anything else act up when the engine quit running?