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. Engine Oil Light, Diagnosis & Testing
1.
Understand and validate customer concern.
Inspect visible system components for obvious damage or conditions
that may cause concern.
2.
Inspect for related bulletins, recall/field
actions and preliminary information.
...