Well, Debi, you are right that noise is a factor in some of
the intermittant operation vanagon engines, and noise is best detected
by analog means since it's an analog signal.  However, we need to
model the actual system to know what to measure.

The vanagon engine is sometimes an open loop, and sometimes a closed
loop feedback control system.  The type of problems we see
can be caused by noise, oscillation, and dynamic range limitations.

If any other list members who have knowledge about
feedback systems and vanagons who would like to start a sub group to
determine a rigorous and effective way to troubleshoot intermittant
operation, please p-mail me.  This should be a solvable problem.

(My van is listening, so this is probably a good way to make sure it
is never intermittant again.)

Cheers, Tom Neal