Hello, I have been having some idle issues for a while now on my 89 GTI PB. One time after a while of full throttle my idle RPM suddenly went up to 2000 RPM, which can be rather obnoxious as you can imagine. I tried dialling it back using the idle screw at the throttle body but that only was a temporary fix and gave a rough idle. Also when the car was up to temp it had a slightly sticky throttle resulting in funky gear changes as the RPM went up when pushing in the clutch. The 2000 RPM also meant whilst driving it was trying to keep it there too, which makes for interesting roundabout strategies as I don’t want to cook my brakes either. So after having the issue for a while and dialling the screw back each time I notice the problem returns when I’m either on full or nearly full throttle the idle RPM shoots up. So I am also thinking of it maybe being a sticky throttle body or something like that. Now I’m no mechanic so don’t know where and what to check the best so was wondering what you guys think. Thanks!
Check your throttle cable isn't frayed. The idle stabilisation valve might benefit from a good cleaning too.
I would suggest going through a few things while you are at it: Clean the ISV Check throttle cable for any issues Clean the throttle body with carb/inlet cleaner (they can get covered in old sticky oil from the breather). Might also be worth popping the lid off the AFM and cleaning the contact strip with some electrical contact cleaner. It doesn’t sound like the issue is a vac leak but can’t hurt to look those over while you are at it as well.
cable first as said, if its the original will prb be well past it. while you're fitting make sure the throttle lever is pulling the cable straight thru the hole in the bulkhead, they're easy to bend. when setting tension have someone hold pedal to floor and set the throttle so its only just wide open. setting too tight is what often bends the throttle pedal and once its off on the wonk the cable starts chewing itself to pieces once thats done, read this: https://clubgti.com/forums/index.ph...ose-and-tune-your-mk2-digifant-gti-8v.124949/
