Thanks for the help Jim. While cleaning the throttle valve switch with a blast of water from my hose in preparation for checking it, I recalled that once before having the same problem and it was the Temp II switch. (Mark Drillock then suggested I check it.) Then and now I gave it a wiggle and the van now seems to work perfectly again. Could it have been that simple? A loose or poor contact or corroded contacts on the Temp II switch?

William

  if you have a bently the switch is under the throttle valve -digifant-24.59 and what i called the butterflyis what the accelerator cable is attached to. to chech is on 24.58 and 24.59 24.60 to 24.62 to check the wireing to cpu.
  Do not squart brake cleaner around this switch.. It will eat the plastic and the switch will not work.( BTDT oops )

  Jim Morgan 86GL
  "Breadbox" 205,000.0
  Westlake,Ohio