octane GMC SIERRA 1998 Owners Manual

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/! CAUTION:
You can be injured and your vehicle could be
damaged
if you try to do service work on a
vehicle without knowing enough about it.
Be sure you have sufficient knowledge,
experience, the proper replacement parts and tools before you attempt
any vehicle
maintenance task.
Be sure to use the proper nuts, bolts and
other fasteners. “English” and “metric”
fasteners can be easily confused. If you use
the wrong fasteners, parts can later break
or fall off.
You could be hurt.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the airflow around
it. This may cause wind noise
and affect windshield washer performance. Check
with
your dealer before adding equipment to the outside of
your vehicle.
Fuel (Gasoline Engine)
If your vehicle has a diesel engine, see “Diesel Fuel
Requirements and Fuel System”
in the Diesel Engine
Supplement. For vehicles with gasoline engines, please.
read this.
Use regular unleaded gasoline rated at
87 octane or higher.
At
a minimum, it should meet specifications ASTM D48 14
in the United States and CGSB 3.5-M93 in Canada.
Improved gasoline specifications have been developed
by
the American Automobile Manufxturers Association
(AAMA) for better vehicle performance and engine
protection. Gasolines meeting the
AAMA specification
could provide improved chiveability and emission control
system protection compared to other gasolines.
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Be sure the posted octane is at least 87. 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 87 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 norlnal,
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. If this occurs, return
to your authorized
GM dealer for diagnosis to determine
the cause
of’ fdilure. 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 contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl
(MMT);
ask your service station operator whether or not his 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
GM dealer for service.
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