Idle fluctuates - sticky ISV

[four.rings@MCIONE.com]

Hello, folks.

What's the consensus on disassembling the ISV, is it doable at all?

The idle fluctuates between 1200 and 1600 rpms with the frequency of
about 0.5Hz.
I tested the T°-re sensor as per Scott Mockry. It was 1.2k @ 18°C,
60ohms @ 93°C. No problems here.
Then I unplugged the electrical connector from ISV, as per Paul Heneghan
and Phil Payne. No change in rpms. Aha! - thinks me, wetting the
contacts with a couple of droplets of DeOxit. Plugged-unplugged it
several times, to scrape the oxide film from the contacts as per Ned
Ritchie.
Turned the ignition off to erase the knowledge that the ISV was ever
disconnected. Started the car. Same thing. Evidently the contacts were
fine.

Frustrated, whacked the ISV with the fist. The idle dropped back to 800
rpms and sat there rock solid. Sticky ISV!

When the engine was apart, I couldn't resist the temptation to clean up
the ISV (for the first time in 10 years of the car's life) and in my
useless quest for perfection and unwarranted zeal, I washed the ISV in
the carb cleaner, then in the brake cleaner, then in hot water.
Looks like I damaged whatever was inside the ISV. Has anyone ever
successfully taken it apart AND reassembled it back?

-- 
Igor Kessel
'89 200TQ -- 18psi (TAP)
'98 A4TQ -- nothing to declare
Philadelphia, PA
USA