thanks everyone for the info. for my Vanagon.  I am going to be very busy
checking and cleaning all the things you recommended.  You guys are
WONDER-full.  Will keep you up-to-date on my ventures with this problem.  
Again, today it rained and I barely got 1/4 mile and it started the bucking
and even a small backfire then it idled all funky and I just put in neutral
and turned the key off and then back on.  It went for another 1/4 mile and I
did it again.  Thank goodness I only had 1 mile to go.  I am sure you guys
are sick to death with the subject.  I have 3 mechanics telling me to call
them when I figure it out for they are very intrigued with this problem.  

Stace
91 Vanagon (haven't named her yet)