Cadillac 2009 STS, Owner'S Manual

Page: 332 / 514

If the vehicle has the 4.4L V8 engine (VIN Code D), use
premium unleaded gasoline with a posted octane rating
of 91 or higher. For best performance, use premium
unleaded gasoline with a posted octane rating of 93.
In an emergency, you can use regular unleaded gasoline
with an octane rating of 87 or higher. If 87 octane fuel is
used, do not perform any aggressive driving maneuvers
such as wide open throttle applications. You might also
hear audible spark knock during acceleration. Refill the
tank with premium fuel as soon as possible to avoid
damaging the engine. If you are using gasoline rated
at 91 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 5-7
for additional information.
California Fuel
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 might fail a smog-check test. See Malfunction
Indicator Lamp on page 3-66. 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 the vehicle warranty.
5-6