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Tire Pressures for High Speed Operation
The manufacturer advocates driving at safe speeds
within posted speed limits. Where speed limits or condi-
tions are such that the vehicle can be driven at high
speeds, maintaining correct tire inflation pressure is very
important. Increased tire pressure and reduced vehicle
loading may be required for high-speed vehicle opera-
tion. Refer to original equipment or an authorized tire
dealer for recommended safe operating speeds, loading
and cold tire inflation pressures.
WARNING!High speed driving with your vehicle under maxi-
mum load is dangerous. The added strain on your
tires could cause them to fail. You could have a
serious accident. Don’t drive a vehicle loaded to the
maximum capacity at continuous speeds above 75
mph (120 km/h). Radial-Ply Tires
WARNING!Combining radial ply tires with other types of tires
on your vehicle will cause your vehicle to handle
poorly. The instability could cause an accident. Al-
ways use radial ply tires in sets of four (or 6, in case
of trucks with dual rear wheels). Never combine
them with other types of tires.
Cuts and punctures in radial tires are repairable only in
the tread area because of sidewall flexing. Consult your
authorized tire dealer for radial tire repairs. STARTING AND OPERATING 317
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Compact Spare Tire — If Equipped
The compact spare is for temporary emergency use with
radial tires. It is engineered to be used on your style
vehicle only. Since this tire has limited tread life, the
original tire should be repaired (or replaced) and rein-
stalled at the first opportunity.
WARNING!Temporary use spare tires are for emergency use
only. With these tires, do not drive more than 50 mph
(80 km/h). Temporary-use spare tires have limited
tread life. When the tread is worn to the tread wear
indicators, the temporary use spare tire needs to be
replaced. Be sure to follow the warnings, which
apply to your spare. Failure to do so could result in
spare tire failure and loss of vehicle control. Do not install a wheel cover or attempt to mount a
conventional tire on the compact spare wheel, since the
wheel is designed specifically for the compact spare.
Do not install more than one compact spare tire/wheel
on the vehicle at any given time.
CAUTION!Because of the reduced ground clearance, do not take
your vehicle through an automatic car wash with the
compact spare installed. Damage to the vehicle may
result.318 STARTING AND OPERATING
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Limited Use Spare — If Equipped
The limited use spare tire is for temporary emergency use
on your vehicle. This tire is identified by a limited use
spare tire warning label located on the limited use spare
tire and wheel assembly. This tire may look like the
original equipped tire on the front or rear axle of your
vehicle, but it is not. Installation of this limited use spare
tire affects vehicle handling. Since it is not the same tire,
replace (or repair) the original tire and reinstall on the
vehicle at the first opportunity. WARNING!The limited use spare tires are for emergency use
only. Installation of this limited use spare tire affects
vehicle handling. With this tire, do not drive more
than 60 mph (100 km/h). Keep inflated to the cold
tire inflation pressure listed on either your tire
placard or limited use spare tire and wheel assembly.
Replace (or repair) the original tire at the first
opportunity and reinstall it on your vehicle. Failure
to do so could result in loss of vehicle control.
Tire Spinning
When stuck in mud, sand, snow, or ice conditions, do not
spin your vehicle’s wheels above 30 mph (48 km/h).
Refer to the paragraph on “Freeing A Stuck Vehicle” in
Section 6 of this manual. STARTING AND OPERATING 319
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WARNING!Fast spinning tires can be dangerous. Forces gener-
ated by excessive wheel speeds may cause tire dam-
age or failure. A tire could explode and injure
someone. Do not spin your vehicle’s wheels faster
than 30 mph (48 km/h) for more than 30 seconds
continuously when you are stuck, and don’t let
anyone near a spinning wheel, no matter what the
speed.
Tread Wear Indicators
Tread wear indicators are in the original equipment tires
to help you in determining when your tires should be
replaced. These indicators are molded into the bottom of the tread
grooves. They will appear as bands when the tread depth
becomes 1/16 inch (2 mm). When the tread is worn to the
tread wear indicators, the tire should be replaced.
Many states have laws requiring tire replacement at this
point.320 STARTING AND OPERATING
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Life of Tire
The service life of a tire is dependent upon varying
factors including but not limited to:
• Driving style
• Tire pressure
• Distance driven
WARNING!Tires and spare tire should be replaced after six
years, regardless of the remaining tread. Failure to
follow this warning can result in sudden tire failure.
You could lose control and have an accident result-
ing in serious injury or death. Keep dismounted tires in a cool, dry place with as little
exposure to light as possible. Protect tires from contact
with oil, grease, and gasoline.
Replacement Tires
The tires on your new vehicle provide a balance of many
characteristics. They should be inspected regularly for
wear and correct cold tire inflation pressure. The manu-
facturer strongly recommends that you use tires equiva-
lent to the originals in size, quality and performance
when replacement is needed (refer to the paragraph on
“Tread Wear Indicators”). Refer to the “Tire and Loading
Information” placard for the size designation of your tire.
The service description and load identification will be
found on the original equipment tire. Failure to use
equivalent replacement tires may adversely affect the
safety, handling, and ride of your vehicle. We recommend
that you contact your original equipment or an autho-
rized tire dealer with any questions you may have on tire
specifications or capability. STARTING AND OPERATING 321
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WARNING!• Do not use a tire, wheel size or rating other than
that specified for your vehicle. Some combina-
tions of unapproved tires and wheels may
change suspension dimensions and performance
characteristics, resulting in changes to steering,
handling, and braking of your vehicle. This can
cause unpredictable handling and stress to steer-
ing and suspension components. You could lose
control and have an accident resulting in serious
injury or death. Use only the tire and wheel sizes
with load ratings approved for your vehicle.
• Never use a tire with a smaller load index or
capacity, other than what was originally
equipped on your vehicle. Using a tire with a
smaller load index could result in tire overload-
ing and failure. You could lose control and have
an accident.
• Failure to equip your vehicle with tires having
adequate speed capability can result in sudden
tire failure and loss of vehicle control. CAUTION!Replacing original tires with tires of a different size
may result in false speedometer and odometer read-
ings.
Alignment And Balance
Poor suspension alignment may result in:
• Fast tire wear.
• Uneven tire wear, such as feathering and one-sided
wear.
• Vehicle pull to right or left.
Tires may also cause the vehicle to pull to the left or right.
Alignment will not correct this condition. See your dealer
for proper diagnosis.322 STARTING AND OPERATING
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ENGINE RUNAWAY
WARNING!In case of engine runaway due to flammable fumes
from gasoline spills or turbocharger oil leaks being
sucked into the engine do the following to help
avoid personal injury and/or vehicle damage:
1. Shut off engine ignition switch.
2. Using a CO 2
or dry chemical type fire extin-
guisher, direct the spray from the fire extinguisher
into the grille on the passenger side so that the spray
enters the engine air intake.
The inlet for the engine air intake is located behind the
passenger side headlamp and receives air through the
grille FUEL REQUIREMENTS
Fuel Requirements (Gas Engines)
The 5.7L engine is designed to meet all
emissions regulations and provide satisfac-
tory fuel economy and performance when
using high quality unleaded gasoline hav-
ing an octane range of 87 to 89. The manu-
facturer recommends the use of 89 octane
for optimum performance. The routine use of premium
gasoline is not recommended. The use of premium
gasoline will provide no benefit over high quality regular
and mid-grade gasolines, and in some circumstances
may result in poorer performance.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and immediate service is
required. STARTING AND OPERATING 327
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• The use of leaded gas is prohibited by Federal law.
Using leaded gasoline can impair engine performance,
damage the emission control system.
• An out-of-tune engine, or certain fuel or ignition
malfunctions, can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune or
malfunctioning and may require immediate service.
Contact your dealer for service assistance.
• When pulling a heavy load or driving a fully loaded
vehicle when the humidity is low and the temperature
is high, use a premium unleaded fuel to help prevent
spark knock. If spark knock persists, lighten the load,
or engine piston damage may result.
• The use of fuel additives which are now being sold as
octane enhancers is not recommended. Many of these
products contain high concentrations of methanol. Fuel system damage or vehicle performance problems
resulting from the use of such fuels or additives is not
the responsibility of the manufacturer.
NOTE: Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
Carbon Monoxide Warnings
WARNING!Carbon monoxide (CO) in exhaust gases is deadly.
Follow the precautions below to prevent carbon
monoxide poisoning:
• Do not inhale exhaust gases. They contain carbon
monoxide, a colorless and odorless gas which can kill.
Never run the engine in a closed area, such as a
garage, and never sit in a parked vehicle with the330 STARTING AND OPERATING