What could be the cause of a rather jerky sound (almost like a rubber band unwinding) when I turn the wheel slowly to right or left on my 2001 Sable. The car handles fine on the road, road but continually makes this strange sound when making slow turns.

 

You didn't say a jerky feel but a jerky sound. Could it be a belt squeaking from a loose or worn belt? I'm assuming it the steering wheel turns ok, but there is a jerky sound. If there is also a jerky feel, it could be a loose or worn belt, or both. If it isn't the belt then that leaves the pump or steering gear, but usually when the pump fails, it either doesn't work very good or leaks.