I am asking this question for my dad. He has a 91 pontiac GRAND PRIX I know this is a bonneville forum but the problem may be able to be resolved as a general problem. I own a 2000 SSEI and I have great luck with knowledgable people on here so I am going to ask the question here.....anyway....Like I said, it is a 1991 Grand Prix LE with a 3.1. He has quite a few miles on it and just recently it would just die going down the highway! No sputter, no precursor, just DIE. It would start back up fine and then die again. Does this sound like an electrical issue? Maybe an alternator?? Coil pack?? Ignition module?? We are stumped. Thanks!!!

since this is not a 3800 motor it will most likely be moved to the lounge

it could be something to do with maybe the fuel pump overheating or dieing and not working but getting better later, but electrical is my first guess

check the connection to the ICM, check the battery cables for corrosion. check other grounds related to the ignition system and the fuel pump....usually located on a ground bus somewhere in the car..you'd need a wiring diagram to be certain. those are good places to start

any check engine light ever?

Sounds electrical to me. If it does it on a regular basis, I'd start be reseating all the electrical connectors and checking the ground wire to the motor and chassis.

My 90 Bonneville LE did that too, chased it around for a while and it was the ECM. Replaced it with a junkyard one, and it is still running on that 50k miles later. But, you still need to start poking around the wiring to find out why yours is cutting out completely.

This is going to the Lounge...

I'd start by pulling off the ICM and coils (yes, I know they're a pain to get to on the 3.1), and taking them to a parts store that tests them for free. We'll go from there if those check out ok, but I'm willing to bet one of those is your problem.

I had the same problem with my 93 3.1 GP. Changed out the ECM with a junkyard piece and it'* still going 90,000 later. Also, if you have it scanned, it'll probably come up as the TPS or ign. module. Mine did that, and after replacing those, thats when we figured it out to be the ECM. Just make sure you switch out the PROM.

PROM?? The ECM, that is the computer, right? He said that the check engine light has not come on. He is going to check the electrical connections but you can probably pick up an ECM from the junkyard for pretty cheap (?)

If the module goes out will you still get spark. It will start but then die but will not stay running. Could this be a fuel filter. He ran out of gas on it on Friday and since when he ran it out of gas it has been worse..................