Engine stalls after coming of highway

1993 CADILLAC ELDORADO
117,000 MILES • V8 • 2WD • AUTOMATIC
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GBOYD0507
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After driving twenty miles or so on the highway, the car will shut off, and sometimes it will start back up but sometimes it does not until cooling down. There are no codes coming up but PCM? The transmission will not go into gear until warming up as well, never had transmission problems before and the transmission is fine after warming up for a few minutes. I have had the position sensor replaced, rotor, spark plugs, wires, catalytic converter, 02 sensor, fuel pump, idle control motor, checked for vacuum leaks, water pump, and radiator replaced but still having the same problem. No service engine soon message, but I believe it was just cleared manually. There have been several PCMs changed from wrecking yards and Rock Auto. Any suggestions are deeply appreciated.
Nov 2, 2017 at 4:09 PM
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STEVE W.
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This could be just about anything as it sounds heat related. To try to narrow down the problem you could do a component cooler test. Go to any store that sells "canned air" it is really a refrigerant in the can (actually R134A or a close cousin), when held upright it will spray "air" but if you flip it over it will spray the refrigerant out. Run the car until it shuts down. Try to start it, no start, spray each component one at a time, and immediately try to start the engine.

How have you been scanning it for codes, paperclip? You may need to find someone with a factory OBD I tool, there is a data stream there but without the correct scan tool you cannot see it.
Nov 2, 2017 at 7:55 PM
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GBOYD0507
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I use the warmer button combined with the off button with the key to the car turned in the on position and the codes, if any will appear are only codes that come up as history only. The master mechanic that has looked at my car thinks that it has something to do with the PCM computer that I purchased from Rock Auto. He says that the engine is fine.
Nov 2, 2017 at 9:48 PM
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STEVE W.
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It is possible but in your post you say it has been doing this with multiple PCMs. Is that the case or is it only with the new one? If it did it with those as well it could not be the PCM. It does not mean the issue is with the engine itself.
Maybe grab a spark tester and a fuel pressure gauge and see what goes away when it will not start. That would give you a starting point.
Nov 2, 2017 at 10:18 PM
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GBOYD0507
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Okay, I will have the mechanic try that and respond back to you. Thanks again.
Nov 2, 2017 at 10:25 PM
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GBOYD0507
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I will also have him check the wiring, connectors, and fuses.
Nov 2, 2017 at 10:27 PM
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STEVE W.
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I doubt it is the wiring and such. Those do not usually react to heat that way. They usually just fail and give you fits trying to find the bad spot in the wiring.
Nov 2, 2017 at 10:38 PM
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GBOYD0507
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I took my car to another mechanic and he put a scanner on it for older cars, and it turned out to be the distributor, and that took care of my problem. It hasn't stalled out since replacing the distributor. Also, there was a ground wire that wasn't connected. The ground wire enabled the service engine soon light to go away as well.
Dec 6, 2017 at 8:33 PM
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STEVE W.
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Good Job. Yeah loose grounds can be a pain. Worse when they are connected but are actually faulty. Distributor = bad ignition module. Should have mentioned they go bad, Sorry for missing that.
Dec 7, 2017 at 1:22 AM
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GBOYD0507
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That's okay, I appreciate your recommendations, because it enabled me to explore other remedies that led to finding out what was actually going on. Thank you so much.
Dec 7, 2017 at 4:24 PM
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STRAILER
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Please let us know what you find. We are interested to see what it is.

Cheers, Ken
Dec 10, 2017 at 4:23 PM