Idle quirks

[Christian Hollyer and/or Mike Zappone <zappyer@tiac.net>]

I bought an 85 Audi Coupe GT about two months ago.  I have had a strange
intermittent problem with the idle.
At one point the idle would be fine the next it would randomly bounce
between 500 and 1200 RPMS, After several weeks of this it started suddenly
reving to 3000+ RPMS then idling normally. Within a couple weeks it then
idled constantly at 3000RPMS.  A friend unplugged the idle control valve on
top of the engine.  The car ceased doing all wierd idle things.  So once I
got the cash I purchased a new idle control valve and replaced it.  The car
ran great.  One day the idle was running a little high so I adjusted the
screw down to a little under 1000 RPMS, 5 minutes later it idled back at
1500.  The next day right where I set it, where it has been ever since.
Now the idle has begun to act up again occasionally reving the engine to
2000-3000 rpms and then stopping.  Has anyone out there encountered this
problem, and could you point me in any directions.
ROCK!