98 sunfire 2.2 ok this just started today. after all day with no probs, i went leave to go out and my ps was going in and out. i started just going out when at idle like in a parking lot. but then when i went to come home it was going in and out at random slowing down to turn it cuts out and i almost poped a nut trying to turn 90 degrees to get in my garage. the pump is full and no noises whatso ever. now i can be sure cos it was dark but i poked a cable tie in the pump so i could more easily see the fluid level and the fluid seemed to be kinda black ? belt is fine also. im lost since the pump is full?!?! any ideas greatly welcomed, would be a crappy weekend with no power steering.

my 99 goes in and out all the time with no noise at idle or anything. But if i rev it and hold it at above 2500rpms and turn the wheel back and forth it wines real loud. Pump is also full. It's time for a new pump though i just haven't felt like changing it since i'm doing a 2.4 swap.