Slow Return To Idle
 

I have an 88 944 base model which returns to idle very slowly. Frequently it hovers around 1800 RPM. If I punch the accelerator, it always returns to normal idle immediately. If it's cold outside, it works fine until the engine reaches temperature. If it's hot outside the problem starts immediately. Anybody have any suggestions?

Hi Floman,
Check the throttle cable and reset the TPS-throttle position switch.

Put your ear to the throttle and press the cable. You have to hear an audible click!
If you do not hear the click, loosen up the throttle cable until you do.

Second thing---vacuum lines.
Recheck all lines and especially the intake boot underneath for cracks and all hoses by the ICV/ISV

Replace the pinch clamps with fuel injection hose clamps or the big ones with nonperforated screw type.

GL & welcome
John_AZ
1988 924S + 1987 924S

John, you were right, it was the throttle position switch. I did not realize there was a micro switch inside which you have to listen for.

Many thanks for a simple fix.

Floman