Is the "RPM hold" being discussed really the same as the Rev Limiter? I don't see how the IAC valve could control max RPMs... that is usually done with the ECU.

Okay, another update.

I concluded that I was restricting the air through the solenoid circuit a little too much. When I started the car this morning, the idle didn't get much over about 1000 RPM on a cold start. It was smoother (less air = richer mixture), but the low cold idle speed bothered me. So I found some washers in my junk (miscellaneous hardware) drawer that were the same outside diameter as the hose inside diameter. I changed out the brass fittings having the hole diameter of about 1/8 inch with a washer having a hole size of about 3/16 inch. Tomorrow's cold start will show the effect.

I'm not sure it runs better, but it certainly doesn't run worse.

Don, y'all
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No, this is the sometimes annoying habit of the IAC "holding" the engine revs elevated for a second or two before it drops down to curb idle. It's actually the ECM commanding the IAC to do that. Seems to do it much more in the Summer when the A/C is on. Apparently the older IAC does it more frequently and possibly at a higher RPM.

You'll see this more on the stick shifts when you throw the clutch to come to a stop. You won't see it with the automatics.