Hi, my wife's 2017 500 steers fine under 20mph with City power steering working fine but get up to 40 plus and the steering becomes heavy and sticky - wherever you set the wheel it stays in that position. TYre pressures fine but that shouldnt affect the self centering. Driving at 50 mph is a white knuckle ride. Diagnostics revealed no electrical fault so its mechanical. Im now wondering about pot holes affecting the castor as it wont self centre?... My mechanic thinks intermediate steering column UV joint wear, but that should create some play in steering which there isnt. Anyone had a similar problem?