Code 24: Air control valve?

[Smoothinto2nd]

After searching and finding tons of mildly related subjects or including other issued I figured I'd start a new topic with a very search-able title.

After following this http://legacycentral.org/library/literature/codes.htm and resetting the ecu my car is no longer throwing like 12 different codes. Just 24.

Air control valve / Air control valve inoperative (Abnormal signal produced in monitor circuit)

this apparently: Prevents abnormal engine speed using "fuel cut" in relation to engine speed, vehicle speed, and throttle sensor position

So knowing that and assuming it is the only problem with the car what can be done? Can it be cleaned? If so, how? Does it need to be replaced? If so how much might it cost and how?

Also on what I think is on topic what's the differences between the abbreviations IAC, IACV, ACV if any?

[Legacy777]

What sort of symptoms/problems are you experiencing? You never mentioned that, or if you're just getting a code.

[Smoothinto2nd]

The car is a stock 93 SS 5 speed.

The main issues I'm having right now are a variable idle. I'll start the car up (almost always an easy start cold) and it will have a high idle 1700 to 2500 I also never seem to be get full power (sometimes the car is much quicker than it is other times).

After driving for a few minutes the idle sometimes starts to drop down. Occasionally it will drop to about 500 smoothly after letting of the gas other times it will get to about 1300 then catch itself, drop a little more to like 1200 then catch it self do that a few time then the check engine light comes on. It stays on until I drive off and the RPMs go above about 3000 at which point the light switches off.

[Legacy777]

You can try cleaning the IAC valve as a start. If you remove the top electro magnet piece, make sure you mark it's position in relation to the valve before you remove it.

I'd also check the wiring going from the valve to the ECU and make sure continuity is good.