grand prix 3.1 (idle, spark plug, engine, replace)

[allappliance]

Hello I have a 1994 grand prix 3.1 its been having idle troubles when stopping I've installed new iac, tps, map sensor, thermostat and cleaned the trottle is there something that I'm missing?

[sailordave]

The GM 3.1L is infamous for leaking intake gasket. Not saying this is what's causing your problem. Have you been loosing coolant? Seen stuff mixed with your oil? You may have a leaking intake gasket. It's not cheap to repair unless you're mechanically incline and are capable of doing it yourself without cracking or warping parts. My 2003 Malibu has the same engine and a few years ago had to replace the leaking intake gasket. It's so common a problem that there was a class action lawsuit. I missed my chance to sign up and it's since expired to sign up.

[Tourian]

Sometimes the idle had to be relearned when the battery was disconnected.

[allappliance]

thanks for the reply but not totally gained form your ans.

[southernnaturelover]

Does it totally die when coming to a stop? If so, it could be the TC solenoid in the tranny. It would be like coming to a stop in a stick shift without pressing the clutch.

[Darkatt]

Are you getting a check engine light? Have you checked your O2 sensors? Have you checked your spark plug wires and made sure they are pushed down far enough so you are getting voltage leakage? What about the coils?

I have a 2004, 3800 SC so I am fairly familiar with the engine you have.

Take a water bottle and mist the area around your intake and vacuum lines, if the idle changes, you could have a vacuum leak.