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. Customer Assistance for Text Telephone (TTY) Users
To assist customers who are deaf, hard of hearing,
or speech-impaired and who use Text Telephones
(TTYs), Chevrolet has TTY equipment available at
its Customer Assistance Center. Any TTY user in the
U.S. can communicate with Chevrolet by dialing:
1-800-833-CHEV (2438). (TTY users in Canada can
...