1993 Dodge Grand Caravan mileage: 199,000

While driving under all conditions, power steering cuts in and out making the vehicle difficult to steer. A check of the fluid, drive belt and no leaks is okay. Also, when vehicle is stopped at idle and the wheel is turned slightly left or right, the wheel vibrates and feels as if it is being pushed back repeatedly.

Could this be the internal hydraulics failing of the rack and pinion or the power steering pump?