99 Grand Am Miss & Hard to Start/Idle When Warm

[Racr_X]

1999 Grand Am GT, 3.4L, 100K mi.

This is the 3rd 3.4L V6 99-00 Grand Am I've seen that starts fine every single morning or when the car is cold but then is more difficult to get to start and idle when fully warmed up. When fully warmed up, you must keep your foot on the gas for a few seconds when starting to keep the car running. After a few seconds, let your foot off the gas and the car idles fine. If you don't do the foot on the gas routine for a few seconds, the car just starts and dies. Like I said, this is the 3rd one of these cars I've seen do this so it must be a common problem. Could it possibly be fuel filter?

Also, the current car has a phantom miss, down on power. The weird part is that the miss is bad when first starting the car up in the morning but after driving for a few minutes gets better. It doesn't completely go away but it's better after driving the car a bit. Once again, could the fuel filter cause this ?

By the way, plug wires look new.

[xeroinfinity]

Welcome to AF.

Sound like you need new plugs & wires.
Could have a bad coil or ICM.
If that doesnt fix the problem then your IAC could be dirty or faulty.

Check here for a test procedure for the IAC and cleaning. Tips and Maintenance

A clogged fuel filter can cause simular problems though I dont think thats the problem you are having. If it was then it would run poor warm and cold.
Wouldnt hurt to change it though, should be changed every 20-30k miles which no one does.

Good Luck

[Racr_X]

Originally Posted by xeroinfinity

Welcome to AF.

Sound like you need new plugs & wires.
Could have a bad coil or ICM.
If that doesnt fix the problem then your IAC could be dirty or faulty.

Check here for a test procedure for the IAC and cleaning. Tips and Maintenance

A clogged fuel filter can cause simular problems though I dont think thats the problem you are having. If it was then it would run poor warm and cold.
Wouldnt hurt to change it though, should be changed every 20-30k miles which no one does.

Good Luck

Changed the fuel filter today, slightly better but still not completely gone. What's an ICM ?