The vehicle may have an up-shift light.
When this light comes on, shift to the next higher gear if weather, road, and traffic conditions allow.
See Manual Transmission Operation for more information.
Chevrolet Cobalt Service & Repair Manual. Noise, Diagnosis
A visual inspection must always
be performed to confirm the presence of aftermarket components, potential
collision damage, or areas of concern.
A noise produced by a vibration
can be diagnosed in the same manner as a vibration. A noise produced by
wind, leaks, or ...