Car running crappy

[CJFusco]

Well, this happens every so often, but the old 944 was running really crappy today... idle kept around 750RPM, parking brake light stayed on even though brake was off, clutch was making the same weird sounds that it was making a couple weeks ago (going in for that clutch job this week)... anyone know why the low idle sporatically happens? It will probably be back up around 900 tomorrow, but it is a mild annoyance.

[Andre]

My car idles at 750 rpm all the time.....i didn't think anythign of it but could this be a problem?

[Rollins]

It seems that some 944's run fine at 750 while others don't run so great. My 944 idled at around 1000 and it was very smooth.

[CJFusco]

I have no idea how 'normal' it is, but the engine definitely runs MUCH smoother at 900 than it does at 750.

Experts? What do you think?

[Panzer909]

Would adjusting an idle control valve help, or do you feel the car's problems are deeper than that?

[CJFusco]

The thing is, this is a once-in-awhile thing... so if i adjusted the idle-control, when my car runs normal, it would idle over 1K...

[Magnus_944]

What year is your car?

If it is a 85.5+ you have the more advanced aux air valve that is controlled by the DME to give the right idle speed. If it is broken in some way you might get a strange behaving idle.

If you have a pre 85.5 car you have the old aux air valve which is just controlled by the heat from an electric heat element and the heat from the engine. If this one does not work it will probably get stuck open or closed. If it is stuck open the car will start easy, (as normal) but as it is warming up idle speed will increase. If it is stuck closed car will be harder to start and idle will be to low before the engine is warm.

I don't think will be of very much help, but I wrote it anyway!

/Magnus

[3sonfather]

For starters, you might want to take off your throttle body and give it a good cleaning over with some carb cleaner. Before you do that though, inspect to make sure your throttle switch is working properly. You should hear the slight click as you crack the throttle plate open. Check it with a light probe or ohmeter per Haynes. Next remove the throttle switch so you don't get gunk down inside it. Clear out the vacuum jets and idle metering port. Then put back on your throttle switch making sure it is adjusted properly. Once you're back together, you can readjust the idle air bypass and idle adjustment screw. If this doesnt fix your problem I would diagnose the airflow meter, aux air valve and o2 sensor.

[CJFusco]

Okay, well I slightly adjusted the idle control screw (I have an 83) and the car has a nice, steady idle at 900 and has never run smoother. Thanks for the imput.

I'm thinking i might still clean out the throttle body, though... it couldn't hurt, right?

[Texatl]

Nah, shouldn't hurt at all, just a little sting. j/k Before this did the idle ever change as it warmed up, or if it ran bad would it stay that way????

Rich