Re: 2001 honda accord idle problem!
My guess is going to be air in the coolant system, also. It sounds like it idles fine until the thermostat opens (operating temp). Then the air in the lines affects the IACV reading of the engine temp (from the coolant). There are different approaches to relieving air from the system. I will let you sort through the archives here for the way that works best for you.
Apologizes if you already checked this, but it is easy to overlook. Make sure the level is full when the car is running and at operating temperature.