1990 Pontiac 6000 stalls when hot

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.



Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.


2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.


3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.



Once you have determined which of these functions has dropped out,
you will know which system is having the problem.

I am sure that this is a fuel related problem. When the car is cold, it will start right up. Left alone to idle, it will stall after a period of time. if I give it a shot of ether it will start right up until it has used that spurt of ether. the car will not start at all again until it has set for a while. I get a code 33 which says mass airflow sensor.
I have no mass airflow sensor on this vehicle, but I do have a MAP sensor. Could that be a possible problem in the stalling?

OK, you have proven you have spark. Now complete the rest of the testing.

got spark. got 40 lbs. fuel pressure. got working injectors. car still starts when cold, still stalls abruptly after idling for awhile. Today I revved the engine a few times and it immediately stalled and would not restart.
New fuel pump, fuel filter, MAP sensor, New ECM, new ICM, replaced fuel injector wiring harness as well as the vacuum lines beneath the plenum. Crank sensor checks out OK. Am totally lost on this one. Any suggestions?

You still haven't completed the testing the way it was requested. It is lacking one or more of those functions during the period that it won't start and that is the exact time you have to do the testing.