FORD 2003 Expedition v.4 - Manual (Page 235)

These “aftermarket lift kits” could adversely affect the vehicle’s handling
characteristics, which could lead to loss of vehicle control or rollover and
serious injury.
Tires can be damaged during off-road use. For your safety, tires that are
damaged should not be used for highway driving because they are more
likely to blow out or fail.
You should carefully observe the recommended tire inflation pressure
found on the safety compliance certification label attached to the left
front door latch post pillar (a label may also be found on the fuel cap
filler door). Failure to follow tire pressure recommendations can
adversely affect the way your vehicle handles. Do not exceed the Ford
Motor Company recommended pressure even if it is less than the
maximum pressure allowed for the tire.
Each day before you drive, check
your tires. If one looks lower than
the others, use a tire gauge to check
pressure of all tires, and adjust if
required. Check tire pressure with a
tire gauge every few weeks
(including spare). Safe operation
requires tires that are neither
underinflated nor a vehicle which is
overloaded.
Periodically inspect the tire treads and remove stones, nails, glass or
other objects that may be wedged in the tread grooves. Check for holes
or cuts that may permit air leakage from the tire and make necessary
repairs.
Inspect the tire side walls for cuts, bruises and other damage. If internal
damage to the tire is suspected, have the tire demounted and inspected
to determine whether it needs to be repaired or replaced.
Maintenance and Modifications
The suspension and steering systems on your vehicle have been designed
and tested to provide predictable performance whether loaded or empty
and durable load carrying capability. For this reason, Ford Motor
Company strongly recommends that you do not make modifications such
as adding or removing parts (such as lift kits or stabilizer bars) or by
using replacement parts not equivalent to the original factory equipment.
Any modifications to a vehicle that raise the center of gravity can make
it more likely the vehicle will roll over as a result of a loss of control.
Driving
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