Hi Robert,
I don't want to sound stupid, but what the heck, did you try a new fuel filter?
Don't know what kind of distributor you have, if it has the built-in Hall sender,
like the later model wasserboxers have. But I thought usually they just work or
die completely. It could be the little wiring elbow/harness on the distributor.
It sounds too violent to be the "vanagon syndrome".
Does it also backfire when it lurches?
The most likely cause I would think is a defect in the wiring harness.
Maybe a bad or corroded splice somewhere or an internal tear in a wire.
Keep us posted.
Harald
'90 westy

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