2007 GMC Yukon Owner's Manual - Page 430

However, E85 (85% ethanol) and other fuels containing more than 10% ethanol must not be used in vehicles that were not designed for those fuels. Notice: Your vehicle was not designed for fuel that contains methanol. Do not use fuel containing methanol. It can corrode metal parts in your fuel system and also damage the plastic and rubber parts. That damage would not be covered under your warranty. Some gasolines that are not reformulated for low emissions may contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT); ask the attendant where you buy gasoline whether the fuel contains MMT. General Motors recommends against the use of such gasolines. Fuels containing MMT can reduce the life of spark plugs and the performance of the emission control system may be affected. The malfunction indicator lamp may turn on. If this occurs, return to your authorized GM dealer for service. Fuel E85 (85% Ethanol) The 8th digit of your vehicle identification number (VIN) shows the code letter or number that identifies your engine. You will find the VIN at the top left of the instrument panel. See Vehicle Identification Number (VIN) on page 538. If your vehicle has the 5.3L V8 engine (Code 0) or the 5.3L V8 engine (Code 3), you may use either regular unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85); also see Fuel on page 428. In all other engines, use only the unleaded gasoline described under Gasoline Octane on page 428. Only vehicles that have the 5.3L V8 engine (Code 0) or the 5.3L V8 engine (Code 3) may use 85% ethanol fuel (E85). General Motors encourages the use of E85 in vehicles that are designed to use it. The ethanol in E85 is a "renewable" fuel, meaning it is made from renewable sources such as corn and other crops. Many service stations will not have an 85% ethanol fuel (E85) pump available. The U. S. Department of Energy has an alternative fuels website (http://www.eere.energy.gov/afdc/infrastructure/ locator.html) that can help you find E85 fuel. 430