Every couple of months I have to turn in the idle adjustment screw on my mk1 Rabbit to stop it from shaking... the motor mounts have all been recently replaced so I think that the idle speed really is slowly dropping. Does anybody have experience with a similar situation or an idea of why this might be?
I did have a similar situation quite a few years back, ended up being IP bracket bolts. As I recall one had broken and one had fallen out, leaving the IP bracket only being held on by 2 bolts. Led to rough idling and surging while driving. Can't say that's your problem but it's easy enough to check.
I had the nut that locks it in place loosen up and then the stub would follow shortly there after. Could not seem to get a good position on the nut when I had other WVO hoses in the way.