To clean the tires, use a stiff brush with tire cleaner.
Notice: Using petroleum-based tire dressing products on the vehicle may damage the paint finish and/or tires. When applying a tire dressing, always wipe off any overspray from all painted surfaces on the vehicle.
Chevrolet Cobalt Service & Repair Manual. Emission Control System Inspection
Caution: Do not remove any
component of the engine emission control system. Operating the engine without
the engine emission control system intact will reduce fuel economy and engine
ventilation. This will weaken engine performance and shorten engine life.
The vehicle ...