So im going to bump this thread up before i make a new thread.

But i have a 2005 grand prix GT with similar problems as the OP. Turning left is practically impossible, very hard. Turning right, goes with ease. I checked the fluid and it was low but filled it up and tried to just turn the wheel toget some air out, let it sit overnight and went to work in the AM, turned fine (both ways), pulled into my work (about a 12min drive) tried to take a left turn and again it was impossible. Almost like froze up... Let the car sit until i was done with work about 7 hrs later i went back into the car and it wouldnt turn left again..
I recently put new tierods all 4 on and got an alignment and new tires about 2to3 months ago and never had this problem before.