2003 Pontiac Sunfire?

I have a problem with the AC it was working fine a few days ago, but all of a sudden it wont cool off when parked or when I come to a stop or if I'm going at a slow speed. The AC seems to work fine and cool perfectly when I get some speed. The car makes weird low noises that sound like uninflating a beach ball. Also when I open the hood you notice some type of a tremble at times it seems as if the car's going to shut off. What can be the problem? Thank you any advice will be of great help.