While running some errands today. Car started idling at 2300ish. Drove normal about 10 min. Stopped for about 15 min. Drove another mile and the idle kicked up to 2300. Normally idles at 900. Drove about another mile and stopped car still idling at 2300. Parked for about 10 min. Continued home still idling high. The all of a sudden at a stop sign it was idling normal at 900. Drove it home about 2 miles and it's still idling fine. Any suggestions? Throttle position sensor going out? Oh ya 1987 T2.

Thanks

 

What condition is your vacuum system in?

 

I had an issues like this. Ended up being my secondary throttle plates.

 

Vacuum system is good. Rats nest deleted awhile ago. If it was a vacuum leak wouldn't it be a constant problem?

 

Well, the point for having a large portion of the vacuum system is to help your engine at idle and under low throttle conditions. If you get rid of portions of it, other things get out of adjustment. Did you touch the set screw on top of the throttle body for the primary throttle plate?

Sometimes intermittent vacuum leaks can influence this, so it doesn't hurt to pressure test your intake anyway.

 

Check your throttle. It might not be returning to rest position. Move it by hand the next time it happens or flick the pedal so that it encourages the cable to jump back to rest position.