Ok boys this has me stumped. My best guess is some type of fuel delivery problem BUT it idles fine and drives fine once going so that kinda makes me wonder.. this is a 1990 grand prix 3.1

When I start my car for the first time of the day it starts and drives FINE. However I drove about 10 miles from my house at highway speeds and parked it. 10 minutes later when I start it and go to back up it dies. Starts fine then when I back up i give it tons of gas and it goes without dying. Well I drive it another 10 miles, leave it parked for a half hour. When I go to leave It dies probably 10 times in the parking lot.. I make it to the road giving it gas and it still dies when I let off the pedal to make a turn. It didnt give me any problems the rest of the way home at 55mph but died coming down my driveway after I let off the gas. I know the torque converter solenoids go bad on these and I disconnected it two drives ago.( but OD still works!?)I dont understand why its FINE when cold though and only happens when hot. Usually starts fine after it dies...except yesterday. This problem nearly got me killed yesterday and I wont drive the car till I have it solved..
The car IDLES fine when warm or cold. However after it died on me yesterday in the parking lot about 10 times each time I put it back into park/neutral and had to give it some gas otherwise it would want to die ( and did a few times ) I sat there and revved it for a bit.. then eventually took off and it died when I let off the gas for a yield sign a block away, then died when I got home in my driveway.. Any ideas? The idle speed seems fine normally, it doesnt chug or change speed at idle ( except for yesterday)so I dont think its the IAC. And so far it seems to drive fine out of park IF I give it a bunch of gas and throw it into drive which is obviously bad for the tranny but I had to do it to survive!

Thanks in advance

what rpm is it at usually when it stalls out?

Its an auto without a tach so I dont know. It probably varies a good amount anyway but its at low to midrange rpm's. I thought the torque converter was staying locked up and causing the problems but I unplugged it so now Im thinking its some sensor or fuel problem. Of course those are the things I have no clue about...

Anyone know where I can download a service manual for one of these? I googled but didnt find anything

My 1989 GP SE w/2.8L did very similar to yours, a little different, but I'll share just in case it helps.

Mine would start up fine, accelerate fine but after it warmed up or after a long drive on the highway, if I let off the gas, it would die. It would occassionally be a bit hard to start back up but most times would start back up fairly easily. I got to the point, before I corrected the issue, that I would just give it some brake to stop at lights and signs and such but still give it some gas so it would keep running.

I dont recall it ever dying on me after putting it in gear or something like that, but its been a while since I had that car. It turned out to be the crankshaft position sensor.

Ironically enough, when I got my current GP, shortly after getting it, it started to stall as well. Tach would go to 0, sometimes difficult to start back up, other times Id feel it miss a beat then the TCS light would come on and Traction Control would turn off. Turns out, it too was a crankshaft position sensor. I distinctly remember thinking after figuring that out, that after all this time they STILL have problems with that sensor.

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Scotty Hall
Bartlesville, OK
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it.

The only limitation you will ever face in life is yourself!