Pontiac Repair: 1990 bonnevile stlls again 3800, mass air flow sensor, air flow sensor

Question
Todd you gave me an answer on this on march 27, as of today the following has occurred. I believe we have ruled ot the idle air control. and Have replaced the ecm with a known to work replacement. the vehicle was driven for three days with out even a misfire. Yesturday my daughter topped off the gas tank and drove about 5 miles then it stalled at a light. she restarted it and it misfired until she was able to feather the accelertor pedal and eventually hold it at a high rev and it smotthed out. she then proceded home and i went over picked it up and drove it for an hour stoping starting and no problems whatsoever. when it stalled the check engine light came on but didnt get a hard code help please

Answer
Hi Chris:

wille it could be a few things. I would take a look at the fuel pressure first off. It could be low on pressure and that's why you need to feather the gas to keep it running. If it were a fule pressure issue it may not sent a trouble code. On those older cars it has to run bad for a LOOOOONNNNGGGGGG time before a code would set for low fuel pressure. that's where I would start. Another thought is a mass air flow sensor. you cne unplug it and run the car and see whhat happens. the car will run but it wil have a pretty big hesitation when you step on the gas but it shouldn't stall. give that a try. Back to the fuel pressure issue I think that engine ran on between 35-40 PSI. good luck :}