84 5000S 2.2 5spd High Rev

[Michael Spiers <mikes@specnet.com>]

Alright, I have the problem damn near solved.  After MANY excellent suggestions
yesterday, I went home last night and tried them ALL.  Sure enough, as soon as
I yanked the plug on the Idle Stabilization Valve, the revs dropped from 1,800
to around 650.  The valve is definately working, rattled and carried on just
fine.  I ran TB cleaner through it until I got clear fluid to spurt out the
other side, then hooked it back up.  Boy, when the car's cold it runs like a
dream now!  No fluctuating revs at all, jsut a steady 900 RPM's!  However, once
warm, it jumped straight back up to 1,800.  Damn.  Does this mean the relay is
shot?  Or is it possible that the sender is bad?  I checked my Haynes (no
Beltley yet) last night, and I saw that the relay gets its signal from what
they called a "Thermo Switch," I think.  Is it possible this is bad?  How would
one test it?  If this is the same sender that my temperature gauge uses, then
its good, because the temperature gage is dead-on acurate, near as I can tell.
 I'm dying to use my newly acquired 7678, but I dunno how.  I hooked it up to
the Idle Stabilizer connection, but didn't get a Voltage reading.  Didn't think
to try Ohms.  The connector on my (hers, whatever) has only two wires, not
three.  I just hooked the red clip to a paper clip I shoved on one port on the
connector, and hooked the black clip up to the paper clip I shoved in the other
port.  When I got no voltage reading, I switched the clips, but still got no
reading.  Is there a more scientific way to check this voltage?  Does anyone
know how to check the Idle Stabilizer Relay on these things other than dropping
$150 at the dealer for a new one?  Oh, and by the way, the screw I've been
fooling with IS the right one, according to Haynes (who, by the way, says that
adjusting idle speed is something that only certified Audi technicians can do,
and theat morons with screwdrivers, like myself, shoud stay the hell away from
it, but oh here's a picture of where it is anyway, just don't fool with it!)
 On Turbo cars, like my 87 5kCSTQ, the screw is located up near the right
headlight.  On non-turbo cars, like my (her, whatever) 84 5kS, the screw is
located under the throttle linkage, and up near the right side of the
windshield.  Screw will now come all the way out, but still doesn't do anything
when all the way in.  The Idle Stabilizer, I'm pretty sure, is definately the
culprit.
Thanks to all who have provided so many suggestions!  Hopefully, I can get this
problem solved today!  TIA for any suggestions on how to check the
relay/sender!

-Mike
87 5000CS TQ