GMC 2011 Sierra - Manual (Page 381)

Black plate (87,1) GMC Sierra Owner Manual - 2011
Driving and Operating 9-87
Some gasolines that are
not reformulated for low
emissions can contain an
octane-enhancing additive
called methylcyclopentadienyl
manganese tricarbonyl (MMT);
ask the attendant where you buy
gasoline whether the fuel contains
MMT. We recommend against
the use of such gasolines. Fuels
containing MMT can reduce
spark plug life and affect emission
control system performance.
The malfunction indicator lamp
might turn on. If this occurs,
return to your dealer for service.
Fuel E85 (85% Ethanol)
Vehicles that have a FlexFuel badge
and a yellow fuel cap can use either
unleaded gasoline or ethanol fuel
containing up to 85% ethanol (E85).
For all other vehicles, use only the
unleaded gasoline described under
Recommended Fuel on page 9‑84.
We encourage 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.afdc.energy.gov/afdc/
locator/stations/) 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 malfunction
indicator lamp to come on.
To ensure quick starts in the
wintertime, the E85 fuel must be
formulated properly for your climate
according to ASTM specification
D 5798. If you have trouble starting
on E85, it could be because the
E85 fuel is not properly formulated
for your climate. If this happens,
switching to gasoline or adding
gasoline to the fuel tank can
improve starting. For good starting
and heater efficiency below 0°C
(32°F), the fuel mix in the fuel tank
should contain no more than 70%
ethanol. It is best not to alternate
repeatedly between gasoline and
E85. If you do switch fuels, it is
recommended that you add as
much fuel as possible — do not
add less than 11 L (3 gal) when
refueling. You should drive the
vehicle immediately after refueling
for at least 11 km (7 mi) to allow
the vehicle to adapt to the change
in ethanol concentration.