Gasoline Specifications; California Fuel; Additives - GMC 2007 Envoy Denali Owner's Manual

Gasoline Specifications
At a minimum, gasoline should meet ASTM
specification D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl
(MMT). General Motors recommends against the
use of gasolines containing MMT. See Additives
on page 383 for additional information.

California Fuel

If your 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, your vehicle will operate satisfactorily on
fuels meeting federal specifications, but emission
control system performance may be affected. The
malfunction indicator lamp may turn on and your
vehicle may fail a smog-check test. See Malfunction
Indicator Lamp on page 210. If this occurs, return to
your authorized GM dealer for diagnosis. If it is
determined that the condition is caused by the type
of fuel used, repairs may not be covered by your
warranty.

Additives

To provide cleaner air, all gasolines in the
United States are now required to contain additives
that will help prevent engine and fuel system
deposits from forming, allowing your emission
control system to work properly. In most cases,
you should not have to add anything to your fuel.
However, some gasolines contain only the
minimum amount of additive required to meet
U.S. Environmental Protection Agency regulations.
To help keep fuel injectors and intake valves
clean, or if your vehicle experiences problems due
to dirty injectors or valves, look for gasoline that
is advertised as TOP TIER Detergent Gasoline.
Also, your GM dealer has additives that will
help correct and prevent most deposit-related
problems.
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