Code 2232 going ape!

["Dan Sinclair" <sinclair@prospro.com>]

BACKGROUND:
Well, I think one of my "fixes" is unraveling.  As some of you are aware, my
'88 90 has an intermittent idle goof.  On occasion, the idle dives to
~400RPM when I decel to a stop, then chugs back up to normal.  It used to
die, rather than bottom out at 400RPM.  The code reported had long been a
2232 - Airflow Potentiometer (and once a WOT code, but it never resurfaced).
My mechanic and I tweaked the Potentiometer to read within the proper volt
range per Bentley, and managed to buy the system a couple hundred RPM - so
now it doesn't die, just comes close.

PROBLEM:
Two days ago the engine check light started blinking almost continuously
with the engine warm.  At idle, the light is quiet.  With the car
stationary, and the engine revved up it remains quiet.  But as soon as you
start driving, the flicker kicks in, and keeps flickering until you stop
again.  It behaves like a jiggling short!?!?!  Code reported, 2232, nothing
more.  I'm losing ground....

THOUGHTS AND THEORY:
I have replacement ISV hoses on order, and I've already changed all of the
standard vacuum lines.  If the ISV hoses don't change the situation, I'm
going to retest the Potentiometer via Bentley, and readjust if necessary.
Next will be a degunking of the ISV itself (I've tried two other ISV units
off functional cars though, and the result on my car was the same).  Any
other suggestions?  I want to believe that the Potentiometer is OK, and that
the code is a function of a vacuum leak or other problem.  Especially
considering the testing of the Potentiometer involves pinching the ISV hoses
with pliers - clearly the Potentiometer would be adversely affected by
leaking ISV hoses or the like.  I also want to believe the Potentiometeris
OK because it is built into the Fuel Distributor and the guesstimate price
from my mechanic was 1200-1500 bucks!!!!   Any suggestions appreciated as
usual.  Thanks.

Dan Sinclair
1988 Audi 90, 69K mi.
Walla Walla, WA (soon to be San Francisco, CA).
Pics&details: http://131.107.68.28/a4.org/registry/details.asp?car=761