I have an 87 syncro Westfalia that I purchased at ~30k miles in 1994. I have since that time had a bucking problem that goes away for long periods of time (years). It is back. I see from the posting that it might be the Westfalia syndrome. This only happens if I drive it for more than 2 hours and if I stop and get gas or some such short cool down it goes away for a hour or maybe for the rest of the trip, or it might return. Sometimes in frustration I keep driving and it goes away again for an indeterminate amount of time. The revs seem to go to zero. Is there a checklist I could follow on this issue?