Doran, there is a chance that what you are suffering from it the dreaded
"Vanagon Syndrome". It has been discussed several times on the List and
can be found in the Archives. I've forwarded one posting  by Malcolm
Holser about "Tantalum caps, idle stabilizer, etc." that I think is
particularly relevant.

You said:
<<I was driving from Massachusetts to Seattle when
around South Dakota the 1990 Vanagon Automatic started
losing power intermittently as if running out of gas
momentarily then coming back on. This happened over
and over every few seconds to few minutes. It would
slow from 65 MPH down to about 30 MPH then would start
revving again. It was very cold at the time but that
may have been coincidental because the symptom
continued when the weather warmed to above freezing.

Also, by applying full throttle the problem was
exacerbated. To get the engine to come back, I had to
ease up on the throttle until the engine decided to
come back to life then I could speed up again.
<snip>>

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