There can be a number of causes for fast idle, but in hot weather, normal operation of the van is to idle quite fast under certain conditions. This seems to occur rarely, in general, but when this occurs:

  • The ambient temperature is relatively hot
  • Air Conditioning is being used
  • The transition to a fast idle will usually occur while stopped (e.g. at a red light)
  • In addition to fast idling, the radiator fans will transition to their highest speed
  • If you don't adjust the pressure on the brake pedal, the increased idle speed may cause the van to creep
  • Fast idling will continue until the ignition is turned off and the van is restarted

Anecdotal evidence indicates that the trasition to a fast idle can be avoided by turning off the air conditioning during stops at red lights. Once the transition has occurred, however, it's too late. Only turning off the ignition and restarting can bring the idle speed back down to normal levels.

Discussions on the ev_update group involving this issue: