1988 Olds 88 cutting out

My elderly mother has a 1988 Olds 88 which is immaculate and well maintained. Several months ago, it developed a problem which her mechanic has not been able to fix. She will be driving along and then with no warning, the engine will die. Twice, she has had it towed, but by the time it got to the garage, it started and ran fine. Her mechanic replaced some sensor (she can't remember which one) and thought he had it fixed, but it happened again. He even drove it home for the weekend, but couldn't duplicate the problem. His next guess is the ignition control module, but can't guarantee it and doesn't want to start charging her for guesses.
Anyway, Mom went out and bought a new car rather than risk getting stranded again. The Olds is now mine if I want it. Not my first choice, but there is a new driver in the family and we can use a free car. Problem is that the car is in the next state, a 3 1/2 hr. drive away. I am reluctant to drive it up without first fixing the problem......or even take the car if it is going to be a diagnostic nightmare.
I would appreciate any advice from Olds gurus on what might be going on, and how to proceed.

No way to tell you exactly what to fix, first what exactly did mech #1 do? Second when it stalls some one will have to check for spark and fuel pressure when it happens, or this will never get fixed without replacing everything.

Thanks for the fast reply...... Well, unfortunately, my mom doesn't know what 'sensor' was replaced. I can talk to the mechanic when I go down there. The fuel pump was replaced last year, so while admitting it might have failed, the mechanic is thinking electronic.....maybe heat related since it starts up after sitting for a while. I'm picturing a loooong drive back up here with it if I have to stop for an hour each time it cuts out. If it stops, and I find no spark, would that confirm the ICM is bad?

No spark especially when hot usually points to the crank sensor or icm, a scanner would see if the rpms showed when cranking/nostart, if none most likely the CPS but it could still be the wiring and/or ICM but the CPS is no.1 suspect under those conditions.

could still be the wiring and/or ICM but the CPS is no.1 suspect under those conditions.

Thanks....so it would be vital to find if the CPS was the sensor that was already replaced.

try replacing the crankshaft postion sensor. its a common problem in this car. just fixed mine now its workin like a charm

Take a lookie at the coil packs also. When they start going bad, they tend to die at operating temperatures and then start up after they have cooled off. They also do not leave a code.

A set of coils is about 80 bucks.

To test, start the engine and remove spark plug wire end w/ insulated pliers (thick rubber-coated handles). if any of the coils have an erratic spark off to one side or don't spark at all, then that is your problem.

No spark especially when hot usually points to the crank sensor or icm, a scanner would see if the rpms showed when cranking/nostart, if none most likely the CPS but it could still be the wiring and/or ICM but the CPS is no.1 suspect under those conditions.
I am having the same problem it has been in the shop I don't know how many times and has been put on the computer to analize it and nothing comes up. This is really frustrating since I don't have the money to have it in the shop all the time. Please Help!!!!!!!!!!

Thank you I will try both of these items.