Very High Idle ISV Problem

[John Sherrow]

In my experience if you can blow air through the ISV from inlet (side
opposite the connector) to outlet (right angle) it is defective. I like
you surmised that engine vacuum was sufficient to pull "metered" air
thru the ISV. The only thing about your situation that is different than
mine is the idle speed. I thought 1800 rpm was a fuel cut off point when
at idle. Might want to check the throttle position switch.