The tire pressure is low.

Adjust the tire pressure. Refer to Tire Inflation Pressure Specifications in Maintenance and Lubrication.

The suspension or the ball joints lack lubrication (worn/contaminated joints).

1. Lubricate the joints.

Re-lubricate the joints at proper intervals.

2. Replace the joints, if needed. Refer to Lower Control Arm Ball Joint Replacement in Front Suspension.

Binding is present in the following components:

Replace all of the affected parts.

The steering gear to the column is not in alignment.

Align the steering column. Refer to Steering Column Replacement in Steering Wheel and Column - Tilt.

The pump belt slips.

Replace the belt. Refer to Drive Belt Replacement 4.3L or Drive Belt Replacement 4.8L,5.3L,6.0L in Engine Mechanical.

The fluid level in the reservoir is low.

1. Fill the reservoir to the proper level.
2. Inspect the lines and the joints for external leakage.

The steering gear or the pump leak internally.

Refer to Power Steering System Test .

The front wheels are not in alignment.

Inspect the wheel alignment. Refer to Wheel Alignment Specifications in Wheel Alignment.