1990 gst idle

[funkbuster]

Ok, here I am, with the typical newbie question only mine is more complicated. Started idleing really low, adjusted it to normal idle. Drove it for about 2 weeks, then out of the blue it started idleing high. New biss o-ring and tried adjusting that and all, but it still wants to idle high, around 2k. Cleaned throttle body. I have read it could be plug wires or vacum leak. What is you guys/gals opinions on it? Thanks in advance for help.

 

[Old Mitsu Tech]

Well, one of two things or a combo of the two. The idle air controller is a stepper motor and can just go bad. It can just be that, or if it shorts out, it can take the control circuit out of the power train control module.

I don't have the ohm specs, but you should be able to locate that. Check both sides. Extend and retract.

If one comes up shorted, replace the iac and hope that it didn't get the pcm.

Good Luck

 

[paul s]

The ISC resitance(ohm) should be around 30ohm between pin 1-2, 2-3, 4-5, 5-6.