The problem was caused by the Idle Control Unit cable coming in contact with the power steering pump pulley. Two wires were severed, I repaired the wires and secured the cable with a wire tie. 

I had recently relocated the ICU from behind the taillight to accommodate an oil cooler and just tucked the ICU cable out of the way. Washboarding on the road from Hurricane Ridge to Obstruction point must have caused the cable to move enough to contact the pulley. Self inflicted injury.

-Mark

> On Aug 14, 2024, at 2:42 PM, Mark McCulley <mark@MARKMCCULLEY.COM> wrote:
> 
> Van started revving up above 2500 rpm after starting, happened a couple of times then stumbled and quit. Restart and same pattern occurs. 
> 
> I reseated all the connections in engine bay, still same symptom. Disconnecting the idle control unit removed a the idle surge and allows van to be drivable, though idle is too low. 
> 
> I’m a few hours from home, thinking it’s ok to drive home without the idle unit.
> 
> Any comments or suggestions?
> 
> -Mark
> 1987 syncro