one that actually does work

[studley07]

HI After a idle control valve for a 1990 Quattro 2.3 20v 7a engine. Looking for a working one please, unlike ebay that claimed all parts work so I bought an ICV that didn't! anyone got one for sensible money i'm interested.Cheers

[Lago Blue]

You've tried the soaking/cleaning/(type dependent) dis-assembly routines as applicable , particularly the "clean again" part, correct?

See "Wandering Idle":

http://www.20v.org/engprob.htm

Looking at your other posts, consider that it may be you may also have a vacuum leak elsewhere (similar to the O-ring suggested in above link) that won't reveal itself by a simple external visual inspection, but may with a smoke test.