89 200q ISV function

[Ed Kellock]

My ISV is keeping the idle speed elevated most all the time once the engine
warms up most of the way.
 It's operation seems appropriate when cold and warming up, then it'll keep
the idle at 1000 to 2000 until I blip of the throttle.
 I've cleaned it very well. I even made a rig with a 9 volt battery and a
switch to keep it open so I could do better cleaning.
 I don't believe my issue is due to any crud in it anymore because when the
idle seems elevated, even if it's only 1000 rpm (no a/c or rad fan running),
if I unplug it the idle immediately drops to a steady, even 800.
 So I'm trying to figure out what might be triggering it to raise the idle
speed when it doesn't seem necessary. I'm going to have a look at the wiring
diagram this evening, but I thought I'd post to see if anybody has any BTDT.
 Thanks,
Ed