For 1990-2009 cars

Problem | Action
--- | ---
Air present in fluid. | Inspect and bleed the system. Refer to Power Steering System Bleeding
Fluid is low due to improper initial fill or system leak. | Inspect and fill the system. Refer to Checking and Adding Power Steering Fluid
The pump mounting is loose. | Torque the pump mounting to proper specifications. Refer to Power Steering Pump Replacement .
The power steering gear inlet (pressure) hose is grounding out. | Check and adjust for proper mounting and clearance. Refer to Power Steering Pressure Pipe/Hose Replacement .