The vehicle has improper shock action.

Service and/or replace as needed.

Refer to Shock Absorber Replacement in Front Suspension or Shock Absorber Replacement in Rear Suspension.

The vehicle has excessive tire/wheel runout.

1. Inspect the components.
2. Perform an alignment.

Refer to Wheel Alignment Measurement in Wheel Alignment.

The tire/wheel is out-of-balance.

Balance as needed.

The tire has a blister or bump.

Replace the tire as neccessary.