'87 Shelby Charger: Idle 'jumped'/stayed high, while in neutral after a long ride...

[Wayne in NJ]

Took a friend for a ride, (if I were Italian, like my wife, that would have an ominous meaning), out on the highway, flying along nice, returned home, positioning to back into the garage, (50 point turn...), while out of gear, the idle suddenly accelerated to 4,000± RPM, (not sure the exact RPM, it was kinda freakin me out), and, despite tapping the gas pedal to kick it down, it stayed up there.

My friend, being a gear head, and former 4cylinder turbo owner (Mitsubishi Mirage, I think), had me shut it off to inspect the accelerator cable for sticking/etc. No sign, started it back up, it was back to normal...

Any thoughts?

[Shadowv4l]

the fact that it changed just by restarting the car makes me think IAC issue

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and revving the car wont make a stuck IAC move but everytime you start the car I think the IAC motor runs in or out to control idle.

[4 l-bodies]

Sounds like AIS (automatic idle speed) motor. Might check VSS (vehicle spped sensor) too. If it does this again, take the bonnet off the TB and put your finger over the small hole next to throttle blade. See if idle comes down immediately. This is where AIS motor bypasses TB on the pull thru TB's.
Todd

[Shadowv4l]

well since we're spelling things out.... IAC (Idle air control) - TB (throttle body)
lolz

[cordes]

A Vacuum leak in a TI log car will cause the idle to shoot up that high.

[hewhobarksatdogs]

So where is the Idle Air Control motor located?

[DevoBuzz]

On the throttle body. Wires coming out of it. Black cap. Cylinder shaped. I think...ha

[hewhobarksatdogs]

found it! not the problem, though (I think); is vacuum leak where steel pipe, about 3/8 popped out of the intake manifold, top of motor about halfway down the manifold. will figure it out tomorrow. And Thanks for your input!