Black plate (69,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 8/15/13
Driving and Operating 9-69
If the vehicle has a yellow fuel cap,
E85 or FlexFuel can be used in the
vehicle. SeeE85 or FlexFuel on
page 9-71.
For all vehicles except those with
the 6.2L V8 engine, use regular
unleaded gasoline with a posted
octane rating of 87 or higher. If the
octane rating is less than 87, an
audible knocking noise may be
heard. If this occurs, use a gasoline
rated at 87 octane or higher as soon
as possible. If heavy knocking is
heard when using a higher octane
rated gasoline, the engine needs
service. If the vehicle has the 6.2L V8 engine
(VIN Code J), use premium
unleaded gasoline with a posted
octane rating of 91 or higher.
Regular unleaded gasoline rated at
87 octane or higher can be used,
but acceleration could be reduced,
and an audible knocking noise may
be heard. If the octane is less than
87, a heavy knocking noise may be
heard. If this occurs, use a gasoline
rated at 87 octane or higher as soon
as possible. Otherwise, the engine
could be damaged. If heavy
knocking is heard when using
gasoline with a higher octane rating,
the engine needs service.
Use of Seasonal Fuels
Use summer and winter fuels in the
appropriate season. Driving or
starting could be affected if the
incorrect fuel is used. Drive the
vehicle with the engine running until
the fuel is a half tank or less, then
refuel with the current seasonal fuel.
Prohibited Fuels
Gasolines containing oxygenates,
such as ethers and ethanol, as well
as reformulated gasolines are
available in some cities. If these
gasolines comply with the
previousely described specification,
then they are acceptable to use.
However, E85 (85% ethanol) and
other fuels containing more than
15% ethanol must be used only in
flex fuel vehicles.
{Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
damage plastic and rubber parts.
That damage would not be
covered under the vehicle
warranty.
Black plate (70,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 8/15/13
9-70 Driving and Operating
Some gasolines that are not
reformulated for low emissions can
contain an octane-enhancing
additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). Do not use
gasolines with MMT as they can
reduce spark plug life and affect
emission control system
performance. The malfunction
indicator lamp may turn on. If this
occurs, see your dealer for service.
Gasoline Specifications
At a minimum, gasoline should meet
ASTM specification D 4814. Some
gasolines contain an
octane-enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend
against the use of gasolines
containing MMT. See“Prohibited
Fuels" in Fuel on page 9-68.
California Fuel
Requirements
If the vehicle is certified to meet
California Emissions Standards, it is
designed to operate on fuels that
meet California specifications. See
the underhood emission control
label. If this fuel is not available in
states adopting California Emissions
Standards, the vehicle will operate
satisfactorily on fuels meeting
federal specifications, but emission
control system performance might
be affected. The malfunction
indicator lamp could turn on and the
vehicle may not pass a smog-check
test. See Malfunction Indicator
Lamp on page 5-22. If this occurs,
return to your authorized dealer for
diagnosis. If it is determined that the
condition is caused by the type of
fuel used, repairs may not be
covered by the vehicle warranty.
Fuels in Foreign
Countries
If planning to drive in countries
outside the U.S. or Canada, the
proper fuel might be hard to find.
Check regional auto club or fuel
retail brand websites for availability
in the country where driving. Never
use leaded gasoline, fuel containing
methanol, or any other fuel not
recommended. Costly repairs
caused by use of improper fuel
would not be covered by the vehicle
warranty.
Fuel Additives
To keep fuel systems clean, TOP
TIER Detergent Gasoline is
recommended. See Fuel on
page 9-68.
If TOP TIER Detergent Gasoline is
not available, one bottle of Fuel
System Treatment PLUS, part
number 88861013, added to the fuel
tank at every engine oil change, can
help. Fuel System Treatment PLUS
