I'm on the road and several hundred miles from home ( southern CA) and
my 90 Vanagon has begun to run bad. It is missing and has a serious
reduction of power when under load. It starts up and idles, but is
running real rough, no backfiring though. Its almost as if there is a
fouled plug or bad ignition on one of the cylinders Or its running way
too rich. I pulled the plugs and replaced them with clean re-gapped ones
but no improvement. I inspected the plug wires and they are in good
shape, almost new, so I doubt this is a problem, BUT I've seen a bad
plug wire cause this type of behavior before. I cannot imagine that
timing has changed. I should be able to limp back home as once up to
speed the car runs OK and is not overheating and oil pressure is good.

Are there any tips on simple things I can check ( while on the road) to
at least eliminate any other obvious possibilities?

Thanks for any suggestions!

-john