At a minimum, gasoline should meet ASTM specification D 4814 in the United States or CAN/CGSB-3.5 or 3.511 in Canada. Some gasolines contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT).
We recommend against the use of gasolines containing MMT. See Additives for additional information.
Gasoline Octane
California FuelChevrolet Cobalt Owners Manual. Tire Inspection and Rotation
We recommend that you regularly inspect the
vehicle's tires, including the spare tire, if the
vehicle has one, for signs of wear or damage.
SeeWhen It Is Time for New Tires
for more information.
Tires should be rotated every 5,000 to 8,000 miles
(8 000 to 13 000 km). See Scheduled Maintenance. ...