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.
Chevrolet Cobalt Service & Repair Manual. Vehicle Multi-Point, Inspection
A visual inspection must always
be performed to confirm the presence of aftermarket components, potential
collision damage, or areas of concern.
1.
Inspect service history of vehicle.
2.
Inspect engine oil level.
...