octane GMC ENVOY 1998 Owners Manual

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.
0 Be sure you have sufficient knowledge,
experience, the proper replacement parts
and tools before you attempt any vehicle
maintenance task.
0 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
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 Manufacturers
Association (AAMA) for better vehicle performance
and engine protection. Gasolines meeting the AAMA
specification could provide improved driveability and
emission control system protection compared
to
other gasolines.
Be SUI-e 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
LIP 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.
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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 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 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.
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
help clean the air. General Motors recommends that you
use these gasolines
if they comply with the
specifications described earlier.
I NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don’t use it.
It can corrode
metal parts in your fuel system and also damage
plastic and rubber parts. That damage wouldn’t be covered under your warranty.
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