1997 Chevrolet Express Van Owner's Manual - Page 237

Some gasolines that are not reformulated for low emissions containan octane-enhancing additivecalled methylcyclopentadienyl manganese tricarbonyl (MMT); ask your service station operator whether or not his fuel contains MMT. General Motors does not recommend the use of such gasolines. 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 your authorized GM dealer forservice. reformulated gasolines may be availablein your area to help cleanthe air. General Motors recommends that you use these gasolines if they comply with the specifications described earlier. NOTICE: Your vehicle was not designedfor fuel that contains methanol. Don't use It can corrode it. metal parts in your fuel system and also damage plastic and rubber parts. That damage wouldn't be covered under your warranty. To provide cleaner air, all gasolines in the United States are now required to containadditives that will help prevent depositsfrom forming in your engine and fuel system, allowing your emission controlsystem 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