abnormal drag?

[trucknutz]

ok so when i turn my a/c on, my revs at idel seem to drop at half and then bounces back up and keeps going like that... it happens with every single air setting except for the head only.... why?

 

[SoNic67]

Probably the IAC valve is not working properly... Try cleaning it or replace it.

 

[Heavymentill]

While the vehicle is idling observe if the RPM's drop when the A/C compressor engages. This will give you an idea if this is A/C compressor related.