1997 GMC Sonoma Owner's Manual - Page 242

To provide cleaner air, all gasolines in the United States are now required to contain additives that will help prevent deposits from forming in your engine and fuel system, allowing your emission control system to function properly. Therefore, you should not have to add anything to the fuel. In addition, gasolines containing oxygenates, such as ethers and ethanol, and reformulated gasolines may be available in your area to help clean the air. General Motors recommends that YOU use these gasolines if they comply with the specifications described earlier. Fuels in Foreign Countries If you plan on driving in another country outside the find. Never use leaded gasoline or any other fuel not caused by use of improper fuel wouldn't be covered by your warranty. TO check on fuel availability, ask an auto club, or contact a major oil company that does business in the country where you'll be driving. NOTICE: Your vehicle was not designed for fuel that contains methanol. Don't use it. It can corrode metal parts in your fuel system and damage also plastic and rubber parts. That damage wouldn't be covered under your warranty. You can also write us at the following address for advice. Just tell us where you're going and give your Vehicle Identification Number (VIN). General Motors International Product Center 1908 Colonel Sam Drive Oshawa, Ontario L1H 8P7 6-4