Idle Adjusting Screw wont stay tight

[cabrioletme]

1988 VW Cabby, 1.8l.

My idle adjusting screw, (on what i guess would be called the MAF?, just the little screw on the back facing the rear of the car, hard to turn with out getting burnt) will not stay tight. I adjust it to where it idles, but it just tightens itself back down after a little bit of driving and then will NOT idle & I have to re-adjust.

Any ideas on how to fix this? Thanks

[eric4321]

It sounds like the o ring on the idle adjustment screw is shot. I have also put teflon tape on the screw to keep it from wandering out. I also had a lot of junk in the passages in the intake manifold around the idle adjuster. I was able to clean it and everything whith the intake off the car. The p/o of my Cabby was a cheap idiot and siliconed the old intake gasket instead of spending $5 for a new gasket. Well I hope this helps.

[Briano1234]

Replace the 0-ring by going to BORG Auto parts.. (BIG ORANGE RETAIL GIANT) home depot or the like.
Use the Teflon tape and you should be fine. The o-ring is what keeps it in place.

[cabrioletme]

THANKS!

[gull]

Yup. And don't go to the dealer -- they don't have the o-ring, and can only sell you the whole screw, which is surprisingly expensive...

When you take it out to replace the o-ring it's a good time to clean the throttle body. My screw had a big booger of congealed oil crud on the end of it.