The following information appears in the General Motors Owner's Manual for this vehicle.

Use gasoline rated at 87 octane or higher. Improved gasoline specifications have been developed for better vehicle performance and engine protection and could provide improved driveability and emission control system protection compared to other gasoline.

Be sure the posted octane is at least 87. If the octane is less than 87 you may get a heavy knocking noise when you drive. (In an emergency, you may be able to use a lower octane -- as low as 87 - if heavy knocking does not occur. If you're using 87 or higher octane gasoline and you still hear heavy knocking, your engine needs service.

Some gasoline that are not reformulated for low emissions contain an octane-enhancing additive called methylcyclopentadlenyl manganese tricarbonyl (MMT); ask your service station operator whether or not this fuel contains MMT. General Motors does not recommend the use of such gasoline. If fuels containing MMT are used, spark plug life may be reduced and your emission control system performance may be affected. The malfunction indicator lamp on your instrument panel may turn on. If this occurs, return to a qualified service outlet for service.

Notice: Your vehicle was not designed for fuel that contains methanol. Do not use methanol fuel which can corrode metal parts in your fuel system and also damage plastic and rubber parts. This kind of damage would not be covered under your warranty.