Anyone familiar with vacuum leak of some sorts that would be causing the power steering to noticibly rev the engine? The van dangerously lurches forward at idle when the wheel is steering wheel is turned. It then remains at an excessively high idle speed. I can hear a very noticible vacuum leak, but I cant tell if it is coming from the throttle body (Ford dealer's claim and $700 "fix") or perhaps elsewhere -- idle air? power steering pressure switch?

Thanks!

It does sound like a problem that the IAC (Idle Air Control) could cause.
Turning the steering wheel places an additional load on the engine, which will result in the IAC opening up some to maintiain or even increase the engine speed slightly. If the IAC is sticking, then it might not be closing slightly when it should. You might try cleaning it......with some WD-40.....
You remove the 2 little screws, lift it up......hold the IAC upside down in a rag, and spray some SeaFoam (Deep Creep) or WD-40 in to flush out dirt and lubricate it.
It may require replacement of the IAC.

Thanks much! It did turn out to be the idle air control. I cleaned it and much of the problem went away but it still persisted a bit. Since the part was only $80, I replaced it and now everything works great.