6-4
Be sure the posted octane for regular is at least 87 (at least
91 for premium). If the octane is less than 87, you may get
a heavy knocking noise when you drive. If it's bad
enough, it can damage your engine.
If you're using fuel rated at the recommended octane or
higher and you hear heavy knocking, your engine needs
service. But don't worry if you hear a little pinging
noise when you're accelerating or driving up a hill.
That's normal, and you don't have to buy a higher
octane fuel to get rid of pinging. It's the heavy, constant
knock that means you have a problem.
If your vehicle is certified to meet California Emission
Standards (indicated on the underhood emission control
label), it is designed to operate on fuels that meet
California specifications. If such fuels are 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 on your instrument panel may turn on and/or your
vehicle may fail a smog
-check test. See ªMalfunction
Indicator Lampº in the Index. If this occurs, return
to your authorized Vehicle dealer for diagnosis to
determine the cause of failure. In the event it is
determined that the cause of the condition is the type of
fuels used, repairs may not be covered by your warranty.Some gasolines that are not reformulated for low
emissions may contain an octane
-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl (MMT);
ask your service station operator whether or not the fuel
contains MMT. General Motors does not recommend the
use of such gasolines. If fuels containing MMT are used,
spark plug life may be reduced and your emission control
system performance may be affected. The malfunction
indicator lamp on your instrument panel may turn on.
If this occurs, return to your authorized Vehicle dealer
for service.
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent deposits from forming in your engine and fuel
system, allowing your emission control system to
function properly. Therefore, you should not have to add
anything to the fuel. In addition, gasolines containing
oxygenates, such as ethers and ethanol, and
reformulated gasolines may be available in your area to
contribute to clean air. General Motors recommends that
you use these gasolines, particularly if they comply with
the specifications described earlier.
