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 Service & Repair Manual. Valve Cover, Replace
Removal
1.
Loosen vent hose clamp at air cleaner
resonator, air cleaner intake duct clamp at air cleaner outlet resonator.
2.
Loosen air cleaner outlet resonator
to throttle body clamp, located forward of accelerator cable bracket ...