Strange Power Steering issues when hot
 

I just happened to be searching for a way to diagnose my power steering problems correctly

1: I don't have any power steering at low engine speeds.

2: The power steering works perfectly when the car is cold, the hotter it gets the worse it gets.

3: I would say that it's choppy. Meaning, even when the car is hot and the power staring isn't helping me, it does sometimes still assist me some what in turning the wheel.

4:The steering wheel seems to be a bit loose.

I’m thinking a new Power Steering Pump. I replaced the PS fluid reservoir last year due to a leak and noise. I currently have 165,000miles.

What fluid are you using?
I would try flushing & using fresh fluid in another new reservoir.

I had a similar problem where an antifreeze coolant leak was dripping on the belt causing the power steering pulley to slip. It took me forever to find! The steering was fine sometimes, "jumpy" when hot. Just a thought.