'90 regal stalls cold/hot while idling and driving

[kpeters0929]

Hello,
I have a '90 Regal custom with the 3.1 liter. All of a sudden yesterday i noticed on the freeway that it kind of slipped out of 4th gear into 3rd gear with a bang. It did it a few more times until i exited.
While city driving it seemed to run fine, but now it will stall while idling. Weird thing is now it is stalling while driving as well.... random stalling. Car still runs fine, and engine doesn't seem to be misfireing/sputtering.

Today i started to work on it, checked fuel pressure and that was within spec. Did some research and was told it could possibly be the ICM or crank position sensor. Replaced both those and have the same issue. Went ahead and cleaned the throttle body, replaced the IAC and TPS same issue. Ended up swapping the MAP sensor and o2 sensor while i was back there since i had a new one, and still has the same issue.
It doesn't throw a check engine light. I still checked the codes after the car stalls and it gives the code 12 which is normal with the engine off/ignition on.
What i did notice is that it will stall cold and hot. This morning before working on the car i turned it on... started fine, idled for 20 seconds then died. Longest i had it running before dying was a couple minutes but i do notice it is idling REALLY low. So low i barely could tell the car is on while in drive.

Regal only has around 50k original miles on it. I'm thinking if i should change the spark plugs since they haven't been changed for almost a year now, but for some reason i feel like that won't fix the issue since it doesn't sputter. Car does have all new MSD ignition coils, and wires.

Any thoughts?

[kenmolloy]

Torque Converter Clutch (TCC)?, or maybe drivers in PCM ... won't throw a service engine light error. have it scanned see if your getting any other codes like 29 or 26 some codes will not trigger the SES light.

[Truck633]

Sorry I can't be of much help, I am looking at exactly the same issue. I am working on a 93 buick regal with the 3.1 and it runs great, I hooked up the fuel pressure guage and ran it for 1/2 hour until it stalled, It never lost fuel pressure, held 40psi the entire time, after it died, I cranked it over and it sounds like it was a timing issue, it would pop and struggle, but not start. I pulled the TPS out and replaced it and it ran great for 20 minutes, then presto...out of the blue it died again. So there it sits in my driveway waiting to cool down so I can start and drive it for 15 or twenty minutes until it stalls out again, if you come up with an answer, please post it here, and I will do the same.

[skooch]

im having a similar issue with a 2000 regal ls with the 3800. runs great, but once every 3 days dies while im driving, no ses lights, no stored codes, changed ignition control module, fuel pump and filter and relay, if anyone has any advice id appreciate it