If you've been following the list the last couple of days, my '87 Westy has been acting the same way recently.  I had just picked it up from the mechanics who had it for almost two weeks and could not find a problem except that the idle was way off, so they replaced the ISV and IC module.  When I started to work yesterday, the lurching/surging started again. nad the van stalled nearing a stop sign.

I took yesterday off work and spent the day trying to fix it.  I succeeded, or so it seems.  But with this kind of problem, as you probably know, you never know if it's truly fixed or if it just got better temporarily...
Anyway, what I did (per several listmember suggestions.)

Cleaned contacts on the ECU and ECU plug
cleaned contacts on the injector connectors
cleaned throttle body
cleaned hall sensor connector/contacts
replaced fuel filter (unnecessary...the old one was only about 3K or less old, and when I cut it open it was clean)
cleaned ground (to ECU) on top of drivers side head.

If anything made a difference, I think it was the ground on top of the head.  Hard to get to, it was rusted onto the top of the head and definitely needed cleaning. There were two other fat brown ground wires coming from the general ECU location, but I could not see where they ended and could not clean them.
Hope this gives you some suggestions. Keep in touch and let's compare notes as things develop.

Mark Garcia
Alhambra, CA
1987 Vanagon Westfalia (for going slow)
2000 Passat 1.8T 5SPD(for going fast)
1981 Vespa P200E (for just going!)

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