1993 Buick Park Avenue idle problems

[Meghan54]

OK, 1993 Buick Park Avenue, 3.8L V-6, 155K miles.

It starts up immediately but it runs rough at first and you have to keep the rpm's up for a minute to keep it running. Once it warms up a little, then it runs ok.

This is all I know about it....trying to diagnose long distance. Cannot do any testing.

But, any ideas? Thinking it's probably in the idle circuit of the throttle body, maybe IAC?

 

[thedarkwolf]

That was going to be my guess. My old 5.0l mustang was bad about that. Had to pull it out and clean it all the time.

 

[Jimzz]

I would take the IAC valve out and spray it and the throttle body with Carb cleaner. Many times the small passages get clogged up and can cause issues like that.

Also check for vacuum leaks(PCV valve line and others) and get the Mass Airflow cleaner and spray off the MAF sensor.

 

[Meghan54]

Thanks y'all. Kinda what I figured. Guess it's time for some Seafoam spray.....

 

[dtgoodwin]

You could also have a leaking intake manifold gasket. Until the system is in closed loop, it cannot account for the additional air, leading to a lean mixture that causes very rough running during warm-up. Common in later 3800's, and two GMC Yukon's with the 5.3 V8 that I've worked on.

 

[monkeydelmagico]

Thanks y'all. Kinda what I figured. Guess it's time for some Seafoam spray.....

You can use starter spray to test for intake and tubing leaks. Spray it around suspected leaks with engine running. If idle changes you know you've got a vacuum leak.

 

[Spec412]

Maybe fuel pressure regulators ?