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 of the recommended fuel is an important part
of the proper maintenance of your vehicle. To
help keep your engine clean and maintain optimum
vehicle performance, GM recommends the use
of gasoline advertised as TOP TIER Detergent
Gasoline.
The 8th digit of your Vehicle Identification Number
(VIN) shows the code letter or number that
identifies your engine. You will find the VIN at the
top left of the instrument panel. See Vehicle
Identification Number (VIN) on page 427.
Gasoline Octane
If your vehicle has the 3.8L V6 engine (VIN
Code 2), use regular unleaded gasoline with a
posted octane rating of 87 or higher. If the octane
rating is less than 87, you may 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, your engine
needs service.
If your vehicle has the 4.6L V8 engine (VIN
Code Y), use premium unleaded gasoline with a
posted octane rating of 91 or higher. You may also
use regular unleaded gasoline rated at 87 octane
or higher, but your vehicle’s acceleration may
be slightly reduced, and you may notice a slight
audible knocking noise, commonly referred to
as spark knock. If the octane is less than 87, you
may notice a heavy knocking noise when you
drive. If this occurs, use a gasoline rated at
87 octane or higher as soon as possible.
Otherwise, you might damage your engine. If you
are using gasoline rated at 87 octane or higher
and you hear heavy knocking, your engine needs
service.
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