GM Chevrolet Avalanche - Manual (Page 341)

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 does not
recommend 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 E-85 (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 5-104.
If your vehicle has the 5.3L V8 engine (VIN Code Z
only), you may use either regular unleaded gasoline or
ethanol fuel containing up to 85% ethanol (E-85);
also see Fuel on page 5-5. In all other engines, including
the 5.3L V8 (VIN Code T), use only regular unleaded
gasoline.
Only vehicles that have the 5.3L V8 engine
(VIN Code Z) may use 85% ethanol fuel (E-85). General
Motors encourages the use of E-85 in vehicles that
are designed to use it. The ethanol in E-85 is a
“renewable” fuel, meaning it is made from renewable
sources such as corn and other crops.
5-7