I can't speak for all models, but in '95 the IACV is totally mechanical. It works on the same principle as the coolant thermostat and actually has an adjustment... Even though it is NOT recommended to adjust it. The IACV reacts VERY slowly, air bubbles in the cooling system should not affect it like that.

My roommate's '90 Accord uses a very similar valve as my '95 GS-R. The Accord does the same thing you're talking about when it's cold. High idle is about 1600 RPM, but it will suddenly drop then raise and so on until the car is totally warmed up and idles properly.

My theory: High idle is set too high... IACV needs to be adjusted lower. I very much dislike the fast idle circuit and defeated mine by closing the IACV as far as I could. Now "high idle" is about 1000 RPM.

good luck!