Hi, i have a 2000 accord ex V-6 and when my A/C is on and running my idle goes up and down all the time but doesn't always do it. And then when i turn off the A/C it completely stops. I have heard someone say that is a Solenoid of some type. What kind if it is? If not can anyone help???

 

It's the IACV which is the valve that helps control a stable idle. Look for things that I've posted about adjusting the BASE idle & forcing the ECU to re-learn the idle.