I recently got my Cayenne 2008 base, which has a V6 3.6 engine and 65k milage. so far so good. There is a small problem which I want to ask you guys about. When I start the car in a parking lot and get on to the road, I can feel very vibration from steering wheel when the turn is close to 45 degree and speed is low. Is this vibration due to the power steering column or something else? Do I need to plan changing power steering fluid?