Gasoline Octane; Gasoline Specifications; California Fuel - GMC 2007 Acadia Owner's Manual

Gasoline Octane

Use regular unleaded gasoline with a posted
octane rating of 87 or higher. For best performance
or trailer towing, you could choose to use middle
grade 89 octane unleaded gasoline. If the
octane rating is less than 87, you might notice
an audible knocking noise when you drive,
commonly referred to as spark knock. If this
occurs, use a gasoline rated at 87 octane or higher
as soon as possible. If you are using gasoline
rated at 87 octane or higher and you hear heavy
knocking, the engine needs service.
Gasoline Specifications
At a minimum, gasoline should meet ASTM
specification D 4814 in the United States or
CAN/CGSB-3.5 or 3.511 in Canada. Some
gasolines contain an octane-enhancing additive
called methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend against the
use of gasolines containing MMT. See Additives
on page 389 for additional information.
388

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 might be affected. The malfunction
indicator lamp could turn on and your vehicle might
fail a smog-check test. See Malfunction Indicator
Lamp on page 226. If this occurs, return to
your authorized dealer/retailer for diagnosis.
If it is determined that the condition is caused
by the type of fuel used, repairs might not
be covered by your warranty.