I just returned from a Thanksgiving week trip from central Illinois to Silverthorne, CO and back -- about 2400 miles in all.  The van handled the job remarkably in most respects.  Mileage was 17.7 mpg on the westward leg (uphill with an occasional west wind) and 20.1 on the return (downhill with the same wind).  This fall, I redid the valve adjustments and installed a new, more accurate fuel pressure regulator.  I couldn't be happier with the mileage and performance in general.

However, when driving for extended periods of time with the cruise control on, I began to experience Vanagon syndrome.  Sometimes just a little hiccup every now and then but occasionally a gut-wrenching, rod throwing, valve sticking sensation that forced the foot to the clutch pedal and that van to the side of the road while I listened for expensive noises.  I fiddled with turning the key off and coasting for a few seconds and with varying the speed and that seemed to help so I'm pretty certain it is Vanagon syndrome.  I have the info on how to fix this with the tantalum capacitor so I'll attack it  before a trip to Florida and back for Christmas.

Another problem occurred that I have not seen mentioned on the list.  If, after sustained driving at speed with the cruise on, I pulled off onto an exit ramp and slowed down, the van would not rev smoothly.  It would idle, occasionally stall, and rev very slowly regardless of the pedal position until it reached 3k or so and then it would rev at higher rpms OK.  When I stopped for gas or to eat and the van cooled down, it would rev OK until I got on the highway.  I said "cool down" but the engine was not hot, the needle was mid point-between the light and the marker on the cold side and the outside temperatures were in the 30-60 range.  I don't think it was heat related. 

Could this be related to the Vanagon syndrome, which I understand is caused by static electricity affecting the FI computer?  Both problems seemed to go away when the engine was not running for 15 mins. or so.  I plan to check the AFM tracks as well.  Any thoughts are appreciated.

Tom
'71 Westy, '85 Westy, '91 Carat