Gasoline Specifications; California Fuel Requirements; Prohibited Fuels - GMC 2014 Sierra Owner's Manual

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. Use 87 octane rated gasoline
or higher as soon as possible.
Otherwise, the engine could be
damaged. If heavy knocking is
heard when using a higher octane
rated gasoline, the engine needs
service.
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.
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.
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.
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
.
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