PLEASE HELP!! 1999 GTP Start up problem!!

[GTPFlorida]

Good day to all!!! I am currently working out a start up issue with my 1999 Pontiac Grand Prix GTP. The issue began about a week ago and I can't wrap my head around what it could be.

The car turns over just fine and I can rev it once before it dies. If the car sits for a long period of time (~12 hours or more) it will start just fine, idle erratically between 500 and 1700 RPM's for about a minute then finally level out at ~1000 RPM's. If I then turn the car off and back on it will not start again. I started to think it was an issue in the fuel system so I have since replaced the fuel filter, fuel pump and fuel pressure regulator. The issue still exists and is driving me crazy!!

Also, I am NOT getting any kind of check engine light so I can't diagnose this with error codes. Anybody have any ideas or experienced this issue before?? Please keep in mind that I am not a professional mechanic. Thanks in advance for any assistance provided!!

[GTP Dad]

Welcome to AF!!

There are several possible causes. First, remove and clean the Idle Air Control motor on the side of the throttle body and clean it with throttle body cleaner. Just don't move the pintle when you have it off the car. Second, unplug the mass airflow sensor at the throttle body and start the car. If the issue goes away then the MAF is bad and needs to be replaced. They are expensive and don't purchase Cardone re-manufactured units because they are often bad.

I hope this helps.

[GTPFlorida]

Thank you so much for the reply/assist! I'll try both of these over the weekend and reply back with the results! Fingers crossed!!

[GTPFlorida]

GTP Dad- First, let me say thanks again for the assist! I unplugged the MAF sensor this morning and the car fired right up and had no issues idling! Upon reconnecting the sensor the engine would sputter and almost die again. I'll be replacing the sensor as soon as the part gets in!! Thanks again!!!

[Tech II]

Just to backup what GTP Dad said, beware of aftermarket remans.....I had to replace one 3x's before I got one to work....and then it only lasted two days.....