91 cutlass starts runs good stalls after awhile starts right back up car sat about a year

you have a bad igniter ( spark plug coil) you can check by disconnecting each coil and see if theres any change in the rpms if you notice a change the coil is good if not the coil is bad what year is your car?

i had the same issue and i had 4 injectors that were bad(shorted). i replaced all 6 with rebult ones($400) and its starts right up and been runnin fine for a year now..

my sons car did the same thing there is a trans sensor ,that we just unplugged and works fine.(mechanic told us)

May just be bad fuel If it has sat for that long. your fuel can be restored with an additive you can get from any auto parts store.I would try that first to rule that out.

Replace your catalic converter

Sounds like idle air control or cam position sensor. Throttle control valve(sensor)?

i dont know i am having a similar problem with my 91 olds cutlass calais its a 2.5 l 4 cyl and i can drive it and it only happens a couple times a week but the RPM gauge goes crazy and the car stalls out it starts right back up but when i put it back into either reverse or drive the rpm does same thing and car stalls ive had it to 5 mechanics they cant figure it out...im hoping to get help on here

the stalling could be ur torque convertor locked up theres a wiring harness on ur transmission unpluged it see if that helps

Providing that all sensors on the new engine match what you had on old one, You must match the computer to the vehicle it's in. (the computer for my 91 will not run my 95, but the 95 will operate the 91, even though both units appear to be identical) Most scrapyards and parts dealers, have a list of what fits what. Unless the motor you swapped in was a known good one, I would also suspect a possible problem such as a worn timing chain, but definitely would not investigate that 'till you have the correct control system in place. If your old computer was "fried" you must also determine the cause of that condition before putting a new one in, or you could damage that one too.

my car was doing the same it would run while and then stop and it wouldnt start again until it sat a while. It was my crankshaft sensor. works fine on that score now.