I have an 86 turbo 944 and it runs and drives great, but if I drive it for a bit and come to a stop, the idle fluctuates from about 500 to 1500 and keeps doing it. Then it goes away after sitting for a while.

What could be causing this?

~Kyle

 

vac leak, idle air valve, afm, not sure if the reference sensors would.

 

my 951 did this sometimes, i then adjusted the TPS and the idle stabilized (if its faulty, it will make the idle rise). Now i only have idle issues on cold starts

 

My TPS caused the same issues you are having. After I replaced no more problems.

 

I needed a new Throttle Stabilizer valve and it fixed mine.

 

I haven't had a chance to try adjusting the idle, but I do know that when this happens, I can smell the exhaust and it is noticeably richer. Also, my A/F meter goes back and forth between lean and stoic, and just crazy sometimes. Could this be my oxygen sensor?

Thanks, Kyle

 

Do the idle adjustment exactly as Clarks or Lindsey instructions say. Its quick, free, and can save you from buying a ISV or TPS or whatever.

 

+1 ^ And I wouldn't worry to much what your guage says right now. If you have the AEM guage I think you have where it has Stoic on the right..that thing is going to be all over the place unless your WOT. I would pic up a new one later.

 

You can easily fix a faulty TPS. Take the cover off and clean up the contact points. MY guess is that it gets condensation on them when the car sits and it sort of calcifies.

 

Before adjusting fixing or replacing the TPS, witg the engine off just open the throttle by hand and listen for a click. If you hear it as soon as you open the throttle it is fine.

 

There is a click at about 1 degree. When I got the car, I adjusted it because there was no click and had no problems. I'm gonna dig into this weekend and figure it out cause it literally sucks gas down when this condition presents itself.