GM Service Manual Online
For 1990-2009 cars only

Gasoline

All engines are designed to use unleaded fuel only. Unleaded fuel must be used for proper emission control system operation. It's use will also minimize spark plug fouling and extend engine oil life. Using leaded fuel can damage the emission control system and could result in loss of emission warranty coverage. The fuel should meet specification ASTM D4814 for the U.S. or CGSB 3.5 M93 for Canada. All engines are designed to use unleaded fuel with a minimum U(R+M)/2e (pump) octane number of 87, where; R=research octane number, and M=motor octane number.

Ethanol

You may use fuel containing ethanol (ethyl) or grain alcohol providing that there is no more than 10 percent ethanol alcohol by volume.

Methanol

Do not use fuels containing methanol. Methanol can corrode metal parts and also cause damage to plastic and rubber parts in the fuel system.

Methyl Tertiary-Butyl Ether (MTBE)

You may use fuel containing Methyl Tertiary-Butyl Ether (MTBE) providing there is no more than 15 percent MTBE by volume.