Essentials Of Good Fuel Economy; Measuring Techniques - Ford 1998 Mustang Owner's Manual

Maintenance and care
If you replace the fuel filter, replace it with an
authorized Motorcraft part. The customer
warranty may be void for any damage to the
fuel system if an authorized Motorcraft fuel
filter is not used.

ESSENTIALS OF GOOD FUEL ECONOMY

Measuring techniques

Your best source of information about actual fuel
economy is you, the driver. You must gather
information as accurately and consistently as
possible. Fuel expense, frequency of fillups or fuel
gauge readings are NOT accurate as a measure of
fuel economy. We do not recommend taking fuel
economy measurements during the first 1 600 km
(1 000 miles) of driving (engine break-in period).
You will get a more accurate measurement after
3 000 km–5 000 km (2 000 miles–3 000 miles).
The advertised fuel capacity of the fuel tank on your
vehicle is equal to the rated refill capacity of the fuel
tank as listed in the Refill Capacities chart in this
"Owner Guide." The advertised capacity is the
amount of the Indicated Capacity and the Empty
Reserve combined. Indicated Capacity is the
difference in the amount of fuel in a full tank and a
tank when the fuel gauge indicates empty. Empty
Reserve is the small amount of usable fuel remaining
in the fuel tank after the fuel gauge indicates empty.
The amount of Empty Reserve varies and
should not be relied upon to increase driving
range. When refueling your vehicle after the
fuel gauge indicates empty, you might not be
able to refuel the full amount of the advertised
capacity of the fuel tank due to the empty
reserve still present in the tank.
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