Hey Marshal,
     Check the wiring to the distributor.  There are three wires to the hall
effect sensor.  I had problems in wet weather with my van bucking.  It
slowly got worse.  It would do it when the weather was dry.  Eventually my
van quit altogether.  I traced the problem to the hall sensor.  It was
cracked around where it enters the distributor housing.  I had to replace
the whole distributor because no one had just the sensor.

Colin
"Bronze Brick"
'86 Syncro GL