I was filling out a repair shop recommendation for Karl's VW shop list and
thought the list might be interested in the problem that R.C. Imports in El
Cerrito CA (near the BART station) was able to immediately fix that the VW
dealers never had a clue about:

I bought my van new, always serviced it at the VW dealer for the first 6
years.  Whenever I drove over Donner Pass (altitude around 7500') the engine
would start cutting out and stumbling.  This would continue for a few miles
or so.  The next day, still at high altitude everything would be fine and
then coming home to the Bay Area everything would be OK as well.  The
dealers replaced plugs, wires, coils etc.etc.  They always "fixed" the
problem until I went up again.

In '96 I asked RC about it they immediately identified the problem as either
a bad hall effect sensor unit in the distributor or F.I. black box.  I put
off fixing it for a bit (wasn't going skiing!) but then one day it stumbled
and died in El Cerrito.  I towed it to RC, they put in a new sensor and it's
never stumbled again.

Believe it........or not!

Graham
90 GL Country home camper