It is possible you have either an electrical problem, or a water in the gas
tank problem.
If you have cleaned all your grounds and made sure they are all secure and
there (is the main ground strap between the driver's side head and the
firewall there?) then I would suspect either a bad distributor cap or bad
spark plug wires.  Both of these will cause problems in wet weather.

If you have a bad line in your gas tank expansion hose setup (do you smell
gas when near the front of the van or after a fuel-up does your tank leak?)
then water could be getting into your tank and messing things up that way.

Hope this helps.

Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
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