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. Compression Pressures
1.
Ensure engine is at room temperature
and battery is fully charged.
2.
Disconnect wiring from ignition module
and remove spark plugs.
3.
Throttle body valve should be wide
open.
...