Start -- cut out --unable to hold start

My will maintained car recently started to intermittantly stop holding its start – won’t start then will go two weeks not problem then won’t start then it will. It will crank, start and then cut out. My mechanics are stumped as they can’t get it to duplicate the problem, they ahve been in the business for 40+ years --any ideas. The battery has been replaced and the computer reprogrammed. This car is a 1998 with 171,000+ miles. Runs smooth as silk when you can get it to work.

There are a number of things that could cause something like this but let me ask a few questions first.

Have they scanned it for any potential codes?

  1. When it acts up are you saying that it may start up but then stumble and die, along with continuing this for a few minutes until it straightens out?

  2. Or does it start, run momentarily, and then die with no sputtering, etc.?

  3. Will it run if the pedal is held down?

Wild guessing based on skimpy details, I might take a stab at a fuel pump check valve on Number 1 and the Automatic Shutdown Relay on Number 2, although the fuel pump itself can get a case of the stupids sometimes and exhibit varying symptoms depending on how the pump is failing.
Number 3 could point to an Idle Air Valve problem but I’m assuming at this point based on the complaint that the symptom does not fit.

the answer is #2. They have checked for codes, considered the idle air valve. Holding pedal has no effect. Thanks for the ideas

Did anyone check to see if the ignition switch loses contact in the run position? If the switch breaks circuit the engine will stop. Then move to the next part of the circuit step by step. If the ignition switch dies mid run no code will set. Computer thinks you turned off the car.