2006 Chevrolet Avalanche Owner's Manual - Page 355
2006 Chevrolet Avalanche Manual
Page 355 highlights
Fuel 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 5-111. If your vehicle has the 5.3L V8 engine (Code Z), you may use either regular unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85); also see Fuel E85 (85% Ethanol) on page 5-7. In all other engines, use only regular unleaded gasoline. Gasoline Specifications At a minimum, gasoline should meet ASTM specification D 4814 in the United States or CAN/CGSB-3.5 in Canada. Some gasolines may contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT). General Motors recommends against the use of gasolines containing MMT. See Additives on page 5-6 for additional information. Gasoline Octane Use regular unleaded gasoline with a posted octane rating of 87 or higher. If the octane rating is less than 87, you may notice an audible knocking noise when you drive, commonly referred to as spark knock. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If you are using gasoline rated at 87 octane or higher and you hear heavy knocking, your engine needs service. 5-5