Hydraulic Power Assist Steering System problems of the 2007 Nissan Sentra

My one month old car rocks side to side when I turn from a smooth road to a bumppy one, and I feel the road bumps through the tire more so than any other new car. I took the car to saratoga nisson and lia nisson, and they said there was nothing wrong. I was trying to trade it back but I will loose money- not happy .

1-9-07 I purchased a 2007 Nissan Sentra on 1-13-07 the ps light came on and the power steering was out. It corrected itself and drove okay until 1-18, 2007 I took the car to the dealer. The porter drove the car and confirmed the power steering was not working. I had to argue with the service clerk to demand that the vehicle be checked, after talking with the service manager and the sales manager they agreed to keep the vehicle overnight. The next day I receive a call stating that a problem was found and the part had to be ordered. I have not been told what the part is. I still do not have the auto. They are still waiting for part .