Marc,
things that pop into my mind are :
Vacuum leaks - did you go nutty looking for those ? I had one 2.1 that acted
all kinds of 'weird' and I found about a dozen intake leaks in the intake
manifold area.  Made a huge difference fixing those.

the 'adapter harness' that is supposed to prevent Vanagon Syndrome ?
............got one of those on it ?
Won't affect idle .........but if you have a 'runs lousy, looses power, and
shutting it off and restarting makes it go right again for a while, until it
does it again '...........that 'can' be Vanagon Syndrome, which is very well
documented and discussed online in many places.

you wouldn't have a crack in your intake boot would you ?
my main tip ..........'check the basics' .........
and every time you get lost...........go back to checking the basics, until
you are sure , that each 'basic parameter' is working correctly.
I often start with checking compression - also you get to see the spark
plugs doing that, and there might be a clue there sometimes.

and plug wires.........not usually a problem but something that always needs
to be considered.
as does clogged cat or muffler.
I also like a fuel pressure gauge on the fuel rail while I'm sorting through
irregular or non-running .........until I have it running right.
Not likely it's the ECU, but it's always very good to have a spare
known-good one.
For a no-start I like to be sure the ECU is firing the injectors.
A nice test, in the case of a no-start, is to watch the injector spray
pattern of each injector  ( this test is in the Bentley book ) .....
this checks two things........well, 3...............fuel squirts under
pressure, ECU is firing the injectors, and what the spray pattern is.

one thing to always consider in a simple unexplained no-start is that if the
plugs get wet from fuel, and not being fired cleanly, it'll flood......
and that's the only thing keeping it from firing up
really........fuel-wetted spark plugs. So always check for that on a
no-start situation.

"It's just a blockage or leakage of fluids or electrons."
( fluids also include gases btw , not just liquids )
Scott
www.turbovans.com

----- Original Message -----
From: "Marc Perdue" <mcperdue@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, April 02, 2009 1:46 PM
Subject: Idle issues...

> Hi all,
>
> It's good to be back after a multi-year absence of mostly
> good-running, good-funning time with my '87 Westfalia.  I've had a
> number of idle issues with my van over the years, but replaced the
> engine when it threw a rod with a Boston Bob big valve engine several
> years ago.  I was very sorry to find out this week that Bob had passed
> away.  His was a rational and informed voice and he was very
> forthcoming in sharing information and helping me with various
> problems over the years.
>
> I've had a fairly recent and on-going problem which has taken a new
> twist recently.  Here is the run-down:
>
> The problem was initially that the van, an '87 Westy, would run fine
> going to work in the AM.  After work, it would initially run fine, but
> then would start losing power, running rough, and stalling at
> stoplights.  I'd restart and it work fine for a minute.  I had some
> time ago replaced the idle stabilizer control module, cleaned and
> checked the idle stabilizer valve, replaced the Temp II sensor,
> replaced the fuel filter, replaced the gas tank gaskets, replaced the
> O2 sensor, and replaced a number of exhaust system parts (they were
> leaking).  A few weeks ago, I replaced the AFM.  Now the van would
> sometimes stall when it was cold, but seemed to be running better.
> Then one day I was driving to my parents' house, 45 miles away, on a
> very rainy day.  It lost power as if the engine had just turned off.
> I'd turn it back on and it would run for about 10-15 seconds before
> losing power again.  I happened to have a new fuel pressure regulator
> and replaced that, to no avail.
>
> I had it towed to a non-VW shop where they checked lots of stuff like
> grounds, O2 sensor function, spark plugs, and distributor.  They fixed
> a gas
> leak on the passenger side.  They said they didn't know what else to
> do and suggested I have it towed to a VW shop.  On a hunch, I asked
> them to set the valve lash to zero, cold, per Boston Bob's
> instructions for the big valve engine.  It was off.  It ran better,
> and I was able to drive it home, but the idle is still rough as a cob.
>
> I'm sort of at a loss as to what to do next, other than replace the
> ECU, which I have tested, and which meets specs.
>
> And festival season is coming up . . . sigh . . .
>
> Thanks for any light you all can shed on this . . .
> Marc Perdue
>
> PS--Coincidentally, I have an '85 BMW 528e whose radiator broke, and
> an '88 BMW 535 IS with electrical issues, and which decided not to
> stay running at all anymore, both at the same time.  So, I am carless
> at the moment . . .  Waaahhh.....