At 07:12 PM 2/19/2011, John Goubeaux wrote...
>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.

Try to narrow it down.

Remove one plug wire at a time (both ends). If it's a spark problem,
you won't notice much difference when you hit the bad cylinder. If all
4 make it worse, then try fuel. Pull the connector from one injector at
a time - same thing, if you pull one and little change, that's the bad
one.

If that doesn't ID a bad cylinder, then the problem is probably
systemic - bad timing, coil, cap, rotor, computer, fuel pressure,
sensor, etc.