The flow control valve sticks or is inoperative.

1. Clean the valve.
2. Replace the valve, if needed. Refer to Power Steering Pump Flow Control Valve Replacement - Off Vehicle .

Air is present in the fluid.

1. Locate the leak.
2. Repair the leak.
3. Bleed the system. Refer to Power Steering System Bleeding .

The fluid level is low.

Add power steering fluid, if needed. Refer to Checking and Adding Power Steering Fluid .

The pump belt slips.

Refer to Drive Belt Replacement 7.4L or Drive Belt Replacement 6.5L or Drive Belt Replacement 5.0/5.7L or Drive Belt Replacement 4.3L.

The steering gear or the hoses have damage.

Replace the parts, if needed. Refer to Steering Gear Replacement or Power Steering Fluid Reservoir Inlet Hose Replacement or Power Steering Fluid Reservoir Outlet Hose Replacement or Power Steering Gear Pipe/Hose Replacement - Inlet or Power Steering Gear Pipe/Hose Replacement - Outlet or Power Brake Booster Inlet Hose Replacement or Power Brake Booster Outlet Hose Replacement .