You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. SeeMaintenance Record on page 6-17.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the air ow around it. This can cause wind noise
and can affect fuel economy and windshield washer
performance. Check with your dealer/retailer 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 the
engine clean and maintain optimum vehicle performance,
we recommend the use of gasoline advertised as TOP
TIER Detergent Gasoline.
The 8th digit of the Vehicle Identi cation Number (VIN)
shows the code letter or number that identi es your
vehicle’s engine. The VIN is at the top left of the
instrument panel. SeeVehicle Identification Number
(VIN) on page 5-109.
Gasoline Octane
If your vehicle has the 4.2L L6 engine (VIN Code S) or
the 5.3L V8 engine (VIN Code M), use regular
unleaded gasoline with a posted octane rating of 87 or
higher. If the octane rating is less than 87, you might
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, the engine
needs service.
If your vehicle has the 6.0L V8 engine (VIN Code H), use
premium unleaded gasoline with a posted octane rating
of 91 or higher. You can also use regular unleaded
gasoline rated at 87 octane or higher, but your vehicle’s
acceleration could be slightly reduced, and you might
notice a slight audible knocking noise, commonly referred
to as spark knock. If the octane is less than 87, you might
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 could damage the
engine. If you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, the engine
needs service.
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