We just got back from a trip to Washington D.C. My '85 Westfalia performed
well.  The intermittent fuel pump noise wasn't quite as bad, but my idling
problem kept cropping up. When stopping, the idle will occasionally drops
down almost to zero, then catch itself and go up to around 800, then
continue dropping and catching up. Sometimes the engine dies. Usually at
the next stop the idle will drop to about 750 and stay stable. But when we
returned to Atlanta about 4:00, the combination of the I-85 bridge collapse
and normal rush hour traffic caused a massive traffic jam. Going down I-85,
across the north perimeter, and up I-75 took at least 1 1/2 hours longer
than it usually does. After about 20 minutes the idle started acting up
after each of many many stops. It was challenging to start from a position
with my left foot on the brake and the right foot pressing in the
accelerator. The temperature gauge showed only a slight increase. The fuel
pump got a little noisier, also.

Things I've tried recently:
I replaced the fuel pressure regulator, which may have helped a bit with
the fuel pump noise.
I checked the charcoal filter, but the lines seemed to be clear.
I put a vacuum gauge on the fuel line to the filter, but while I had the
gauge on the filter didn't make any noise.

Does this information help someone direct me to what I might look at? It's
hard to work on these problems when they almost never occur when taking
short drives around town.