FORD 1999 F-350 - Manual (Page 198)

4. To install the cap, align the tabs on the cap with the notches on the
filler pipe.
5. Turn the filler cap clockwise 1/8 of a turn until it stops.
If the “Service Engine Soon/Check Engine” indicator comes on and stays
on when you start the engine, the fuel filler cap may not be properly
installed. Turn off the engine, remove the fuel filler cap, align the cap
properly and reinstall it.
If you must replace the fuel filler cap, replace it with a fuel filler
cap that is designed for your vehicle. The customer warranty may
be void for any damage to the fuel tank or fuel system if the
correct genuine Ford or Motorcraft fuel filler cap is not used.
The fuel system may be under pressure. If the fuel filler cap is
venting vapor or if you hear a hissing sound, wait until it stops
before completely removing the fuel filler cap. Otherwise, fuel may
spray out and injure you or others.
If you do not use the proper fuel filler cap, excessive pressure or
vacuum in the fuel tank may damage the fuel system or cause
the fuel system to work improperly in a collision, which may result in
possible personal injury.
Fuel Filter
For fuel filter replacement, see your dealer or a qualified service
technician. Refer to the Scheduled Maintenance Guide for the
appropriate intervals for changing the fuel filter.
Replace the fuel filter 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
Maintenance and care
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