Matthew--

Your stop light episodes sound too familiar.  Unfortunately, it could be
many things.

Possibilities:

grounds -- bad ground could easily do this (and many other wonderful and
exciting things) -- check all of them

afm -- air flow meter not giving proper signals to ecu -- cause could be
sensor itself, connections, grounds, or you need the magical harness on
it (harness only 'fixes' problem if shutting the engine off and
restarting 'fixes' problem)

vacuum leak -- would account for stop light problems, but probably
wouldn't cause detectable surges while driving.  On the 87's you're only
talking about a foot or so of hose (and that's probably being generous)
so if it's been a while, you might as well change them just for the sake
of changing them -- consider it routine maintenance.

O2 sensor -- try unplugging it (single wire is all that you need to
unplug, I think, but you can unplug all 3 to be safe) -- if problem goes
away, you've found the source.  It's safe to drive with it unplugged
until you have the opportunity to replace it.  You WILL want to replace
it as you'll be getting less than optimal fuel economy and performance
with it unplugged.

Coolant temp. sensor (the one that feeds ECU) -- $12 including o-ring
gasket, simple to swap out yourself -- this wonderful little doo-dad
will make your van run (if you can call it running) extremely poor when
it malfunctions.

Those are your most-likely candidates.

Good Luck!
Tonya
87 Vanagon GL Wolfs (still leaking a little oil, but better -- thanks
ALL!  I'm bringing it to the dealer next week for an oil change)
74 S. Beetle