A real perplexing V6 idle problem

["Tim Hoffman" <tim@isnetwork.com>]

Hi-

Just got my '94 90S back from a whole week at our longtime Audi wrench, and
we're stuck.

Immediately after I'd replaced the battery in the car, the idle became high
(~1200) and sometimes surging at any operating temperature, with any load on
engine. No fault codes whatsoever. Vacuum leaks are not present, after much
testing using all methods.

New idle control unit was installed, with no effect whatsoever. Pulling the
connector from the unit sends the idle back to normal. This is how I plan to
drive the car until we get this fixed!

Our trusty wrench has spent 8 hours on this, and can't afford any more time
on it! Any BTDTs on this? Could this be a weird computer problem?

TIA

Tim
94 90S
92 100CSQW
72 100LS Coupe (my first car!)