Like it says in the title, my brother has 1990 Accord LX w/ 100,000 miles and when he turns the AC on the engine Lopes, but only at idle and sometimes intermittenly at idle. There is no power loss and all componets have been checked visually for proper operation (compressor, fans, etc.). Is there a common problem here? Thanks for the advice in advance...

 

yea just after a while that idle air control valve stops working as well as it used to. if you crank up the idle control screw on top of the throttle body it will run like a champ.

turn it counterclockwise until you just start to hear the intake note hiss.

 

I have already taken off the IAC, cleaned and tested it for proper operation. I also turned the idle up and this didn't stop the loping. This all leads me to believe it is the something a little more technical, your advice is appreciated.