The idle is too high and then drops?

[Piccolo]

What happens is when the car is driven or is stopping, the idle is at about 2K. But as the car sits for a second the idle drops back to 1K. Why would it do this? It seems the car idles too high and the computer lowers it. Do we need to take the power from it and reconnect letting the car idle for 5-10 minutes? We never did that but is there anything else we could look for?
P.S. Not my car, for BBoiByron.
Thanks!

<small>[ September 20, 2002, 02:45 AM: Message edited by: Piccolo ]</small>

 

[steevil]

CLean the IAC (Idle AIR control valve). It's the cylindrical thing about 3" long with a small wiring harness attached to it. You can completely dis-assemble it and clean the brass plungers to if you remove the 2 philips screws holding the solenoid on. Use some carb cleaner and make sure it's completely dry before re-installing it. While your at it...examine the throttle body for excessive carbon build-up and give it a good wipe making sure to clean the around the edges of the butterfly.

You can use some carb cleaner for this too but I recommend you spray it into a rag and wipe it as opposed to spraying it directly at the throttle body.

There may be a warning lable on your throttle body denoting a special coating on the inside of the throttle body. If you have this warning, DO NOT USE CARB CLEANER. use a damp rag instead.

more than likely this is your problem

 

[projectSHO89]

The general behavior of your car's idling is correct, it seems that the only real issue is the actual idles speed.

Look for a vacuum leak in or around your manifold and all the vacuum lines.

My 89 idles at around 1.5K indicated while rolling, then drops to just under 1k at rest. An accurate tachometer would be a good idea just to see if you indash unit was displaying the proper engine speed.

Steve
89