Well  I did some more troubleshooting following the tests for the ECU in the Bentley, but it
was what Mark Drillock said that kept me coming back to the oxygen sensor - that the ECU
runs in cold mode, ignoring the O2 sensor until the Temp II sensor said the engine was warm.
Then Laurence Smith sent me an email saying "When you are at the end of your rope with this
problem concentrate and act on Michael's message and all will be well again."

So even though I had cleaned the ground from the head to the chassis and cleaned the brown
wire, I took it apart again, and found that someone (aka me) had stripped some of the
threads from the hole, and the bolt wouldn't stay tight.  So I put in a longer bolt and
tightened it carefully, and it seems to be well behaved now.  As well behaved as an 18 year
old van with 300,000 km on it can be ;-)

I just wanted to thank Mark, Laurence and especially Michael Vickey for their help - it's
reassuring when you keep getting pointers to the same problem, that maybe you missed
something - instead of the usual Vanagon problems where it could be any one of 13 different
things.

Oh, and as a bonus, while I was on a test drive, I stopped by the FLAPS and found the wheel
nuts I needed for my alloy wheels for 2 bucks each.  Bonus!

Cheers,
Keith