if its at the point where it wont turn when in park with out giving the engine some gas change it quick. driving it when its totally dead, aka no more power at all, will kill your rack in no time.

pumps only cost about 70 bucks, and a hour to swap out. you'll need a p/s pulley puller to take your pulley off and put it on the new pump. i think autozone should have a free rental puller, if not you'll need to get one.