2000 GMC Sonoma Owner's Manual - Page 247

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 also damage plastic and rubber parts. That damage wouldn't be covered under your warranty. Most service stations will not have an 85% ethanol fuel (E-85) pump available. Those stations that do have E-85 should have a label indicating minimum ethanol content. Do not use the fuel if the minimum ethanol content is greater than 85%. Your vehicle may not operate properly if the ethanol content is greater than 85%. At a minimum, E-85 should meet ASTM D 5798 specifications. To insure quick starts in the wintertime, the E-85 fuel must be formulated properly for your climate according to ASTM specification D 5798. If you have trouble starting on E-85, it may be because your E-85 fuel is not properly formulated for your climate. If this happens, switching to gasoline or adding gasoline to your fuel tank may improve starting. Mixing gasoline and E-85 in your fuel tank will not cause any problems with your vehicle. For good starting and heater efficiency below 32_F (0_C), the fuel mix in the fuel tank should contain a maximum of 50% ethanol. Fuel E-85 (85% Ethanol) The 8th digit of your vehicle identification number (VIN) shows the code letter for your engine. You will find the VIN at the top left of your instrument panel. (See "Vehicle Identification Number" in the Index.) If you have the 2200 L4 (Code 5) engine, you may use either regular unleaded gasoline or ethanol fuel up to 85% (E-85); also see "Fuel (Gasoline)" listed previously. If you have the 2200 L4 (Code 4) engine or the 4.3L V6 engine use only regular gasoline. Only vehicles with the 2200 L4 (Code 5) engine may use 85% ethanol fuel (E-85). 6-5