Mine does the same thing, but when it wants to. when i back off the throttle it will begin to stop cooling or when i am idleing it will do it then to. when i begin to put the motor under a load it will begin to cool again. when it did it one time i popped the hood and looked at the compressor and the clutch was not engaged. i think some compressors have faulty clutches and disengage and engage at random times. i haven't done anything about, it just does it on its own. you make have a bad clutch and just depends when it will fail?!