So after dealing with my evil idle problem (see below) for over a week,
I gave up a took it to my trusty mechanic. After checking the fuel
delivery, he swapped the ECU, and finally the air flow meter which he
determined to be bad. This was after I had found it to be within spec
(so much for my diagnosis).  I took my van home to try to clean or
re-align the "tracks" of the air flow meter as a last ditch effort, and
it worked!  I don't know how long it will last, but it beats spending
$500 on a new AFM, and I learned a lot about troubleshooting the fuel
injection system. Hope this helps someone out there. Thanks for the
help everybody, Adam

"I have tried to diagnose it for the past week and have had no success.
  Upon starting, it feels like it is running on 3 cylinders and stalls
repeatedly.  Once it is warmed up by careful
manipulation of the gas pedal for about 5-10 minutes, all is well-great
power, throttle
response, 17 mpg.  Exhaust smells a bit rich, but it has for quite some
time.

This is what I have done so far:
Replaced air filter, fuel filter, oil, oil filter, and spark plugs.
Found and replaced 2 broken
vacuum lines. Checked throttle switch per Bentley and found it to be
ok. I have a nicely
humming idle control valve which was cleaned anyway.  Swapped out the
idle stabilizer
control unit with a friends' and got no change in behavior.  Replaced
temp 2 sensor. Cleaned grounds on left head to firewall.  All this has
resulted in no change of cold idle stalling/bucking behavior.

The oxygen sensor doesn't participate in the cold idle loop anyway, so
that is
probably not to blame-right? It was replaced about 40K miles ago. My
air flow sensor had the
"capacitor fix" when I was hunting down Vanagon syndrome a few years
back. Turned out to
be the ECU, which was replaced. "