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 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. SeeVehicle
Identi cation Number (VIN) on page 386.
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 (E85); also seeFuel on page 288.
In all other engines, use only the unleaded
gasoline described underGasoline Octane on
page 288.Only vehicles that have the 5.3L V8 engine
(VIN Code Z) 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 (www.eere.energy.gov/
afdc/infrastructure/locator.html) that can help
you find E85 fuel. Those stations that do have
E85 should have a label indicating ethanol content.
Do not use the fuel if the ethanol content is
greater than 85%.
At a minimum, E85 should meet ASTM
Specification D 5798. By definition, this means
that fuel labeled E85 will have an ethanol content
between 70% and 85%. Filling the fuel tank
with fuel mixtures that do not meet ASTM
specifications can affect driveability and could
cause the check engine light to come on.
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