Scott,

This sounds similar to part of the problems that I had with my van.  I
was not aware of this list at the time and spent lots of $$ as several
mechanics guessed and guessed what to do with it. A least I found one
who would take the new parts out and refund most of my $$ when things
didn't work.  He finally disconnected the idle stabilizer plugs from
that unit and plugged them together, which is what is done when the
wasserboxers are tuned.

It ran rough when it was cold, but it started and ran.  When I
reconnected the unit, problems would reappear, not regularly but soon.
After a while it got to be where they would instantly reappear.  That
was about the time I found the list and the vendors with reasonably
priced parts. Now for under $30 I have a new idle stabilizer, and it has
been running great for a month or so.
Bentley says that the diagnosis of the Idle stabilizer (the green or tan
plastic box on the left side of the engine compartment just in front of
the coil and about the size of a deck of cards) is just what was done.
Unplug - if problem disappears, and reappears when replugged, its
defective.  Get another.  But I ran trouble free for months (@ 8) with
it disconnected - through the winter even.  I think that when it is
dying, it sends (or fails to send) signals to the ECU and the thing
shuts down in some way.  Someone else probably can explain what
happens.

Good luck.  As I am a real novice at this, you now have all of my
knowledge of repair of these beasts that I brought to the list.

Sam
'84 Vanagon