I don't have a problem here, but maybe a solution.

A few months ago, I noticed my rpms would start to drift up when I was stopped at a light, from 600 or so up to about 900. I don't remember it coming back down, but I never sat long enough to see what would happen. I don't think it did it every time, but I'm not sure. It seemed to run fine otherwise. I cleaned the TB, IACV and MAF, but none of that helped. I never got around to seriously trying to figure it out.

Then my alternator went out. I replaced that, and the idle has been steady for a month now. I'm not sure why the alternator would have caused it. Maybe the voltage was fluctuating and that was confusing the ECU? Dunno. This isn't the solution to all bad idle problems, but maybe it's worth checking the alternator if you've got one you can't figure out. That assumes the alty will show a fluctuating voltage if it's going bad, and I have no idea if that's right.

Of course, now that I've posted this it'll probably show up again tonight...