I've got a later model 3000 diesel with power steering and the power steering is very weak. I put a pressure gauge on the outlet line of the pump, and at 1000 RPM, it sits around 200 PSI. If I turn the steering wheel either way, I can see the cylinders slowly responding and it's very easy to outrun them with just the steering wheel. When I hit the stops, either direction, the pressure gauge doesn't change. The steering wheel moves up or down ~.1 inches when turning, and there are no external leaks in the system. I'm guessing the problem is somewhere in the control valve, but I have no idea where to start. Any suggestions would be appreciated.