VWGUYGOESPORSCHE

Good evening or morning to all. Reminder, 81 928 U.S. model with auto trans. So I officially got her started and running smooth but the idle is way high. She is purring but I have to manually push down the trottle to drop the RPMs. Any quick fixes for this or is this one of many things? Thanks in advance to all. Steve

VWGUYGOESPORSCHE

After doing some research, it seems like it could be a multitude of things. So I might be stating the obvious but I think the throttle body mounts broke. Seems as if the throttle body is moving some. I can only assume this would affect the throttle cable if the throttle body is off even a little bit. Thanks again in advance. Steve

Jason89s4

Well, also if your throttle body is that loose there is certainly going to be alot of air coming in....which will increase your idle speed until fixed.
Jason

Petza914

I had an elevated idle issue myself once where the spring that closes the throttle plate wasn't pulling it back strongly enough. I added a helper spring a couple years ago and it has been fine ever since.

Mrmerlin

a higher than normal idle indicates a vacuum leak or mis adjusted idle screw or a stuck throttle cable

fiatrn

here's an imperfect plan to follow to diagnose your trouble:

1 - Remove the throttle cable from the throttle body: if that fixes the idle, the problem is in the cable.

2 - can you move the throttle adjustment by hand to lower the idle? Ie, rev the engine a little and it settles at a high idle, then close the throttle by moving the throttle plate by hand and idle goes to normal? If so, then you have a sticking throttle body (for some reason - messed up linkage, maladjusted throttle plate, etc).

3 - If you can't manually close the throttle plate once it is has settled down to idle speed on its own, but wiggling the throttlebody changes the idle, then the throttle body is not seated properly. Remove and repair.

4 - if none of these effect the idle RPM, then you have a vacuum leak somewhere.

Mrmerlin

could also be a bad vacuum booster,
try plugging the hose to the booster then run the engine

Jam-Bro

I changed my air filters and this is what my TB looked like. Small ring of on the outside. Car runs fine. Smooth idle. Should I clean it or leave it alone?

jcorenman

Welcome! If no complaints then probably not worth cleaning. Oil vapor from the breather system tends to condense in the intake, but you might want to open the throttle and peak past it to see if there is a lake in the bottom of the intake.
It also helps to post the year and a bit of history, or maybe start a new thread with photos for a proper introduction.