Symptoms:
Cold start = Idles at 3000 RPM
Then the idle lowers as the engine gets warmer
Once it gets to 1000 RPM, the idle will start to "bounce".
It will go from 1000 RPM to 2000 RPM back to 1000 RPM back to 2000 RPM, over and over.

Test:

• Remove air intake (so you'll have access to the hole before the throttle butterfly valve)
• Start the car
• Wait for the bouncing idle to happen
• Once the idle starts bouncing, block the hole (as shown in the video)

If the idle still bounces, then it's NOT your IACV the problem
If the idle STOPS bouncing, then it's your IACV the problem

In this video, the IACV that's installed is a BRAND NEW Ultra-Power one, however it's faulty (beware of aftermarket)

and if you do clean your OEM one, make sure it's done properly.
If you cleaned it and it still has the bouncing RPM, try what I do here in the video (covering the hole before the throttle butterfly valve) and if it stops bouncing, then you didn't clean it enough/correctly.

SOLVED: I ended up fixing this issue with another aftermarket IACV, bought from RockAuto: WVE 2H1385 (Fits a 2006 Acura RSX Premium - Canadian model)

I hope this helps!