1999 Mercury Mountaineer fuel cap

3. The fuel cap may not have been properly installed and securely
tightened.
These temporary malfunctions can be corrected by filling the fuel tank
with good quality fuel and/or properly installing and securely tightening
the gas cap. After three driving cycles without these or any other
temporary malfunctions present, theCheck Enginelight should turn off.
(A driving cycle consists of a cold engine startup followed by mixed
city/highway driving.) No additional vehicle service is required.
If theCheck Enginelight remains on, have your vehicle serviced at the
first available opportunity.
Light is blinking:
Engine misfire is occurring which could damage your catalytic converter.
You should drive in a moderate fashion (avoid heavy acceleration and
deceleration) and have your vehicle serviced at the first available
opportunity.
Under engine misfire conditions, excessive exhaust temperatures
could damage the catalytic converter, the fuel system, interior
floor coverings or other vehicle components, possibly causing a fire.
Fuel reset
Illuminates when the ignition is
turned to the ON position and the
fuel pump shut-off switch has been
triggered. For more information,
refer toFuel pump shut-off switch
in theRoadside emergencieschapter.
Air bag readiness
Momentarily illuminates when the
ignition is turned ON. If the light
fails to illuminate, continues to flash
or remains on, have the system
serviced immediately.
FUEL
RESET
Instrumentation
7

Fuel gauge
Displays approximately how much
fuel is in the fuel tank (when the
key is in the ON position). The fuel
gauge may vary slightly when the
vehicle is in motion. The ignition
should be in the OFF position while
the vehicle is being refueled. When
the gauge first indicates empty,
there is a small amount of reserve
fuel in the tank. When refueling the
vehicle from empty indication, the
amount of fuel that can be added will be less than the advertised
capacity due to the reserve fuel.
The FUEL DOOR icon and arrow indicates which side of the vehicle the
fuel filler door is located.
MESSAGE CENTER (IF EQUIPPED)
With the ignition in the ON position,
the message center displays
important vehicle information
through a constant monitor of
vehicle systems. You may select
display features on the message
center for a display of status
preceded by a brief indicator chime.
The system will also notify you of
potential vehicle problems with a
display of system warnings.
EF
ENGLISH
METRICRANGESTATUS
ECONRESETSYSTEM
CHECKOIL CHANGE
RESETFUEL
Instrumentation
15

Forced Downshifts
To gain acceleration in(Overdrive) or Drive (O/D OFF) when passing
another vehicle, push the accelerator to the floor. The transmission will
downshift to the appropriate gear: fourth, third, second or first gear.
FOUR-WHEEL DRIVE (4WD) OPERATION (IF EQUIPPED)
When Four±wheel drive (4WD) is engaged, power is supplied to all four
wheels through a transfer case. 4WD power can be selected when
additional driving power is desired.
If equipped with the Electronic Shift 4WD System, and the
instrument panel control is moved to 4WD Low while the vehicle
is moving, the system will not engage and no damage will occur to
the 4WD system.
All utility-type vehicles and 4WD vehicles have special design and
equipment features to make them capable of performing in a wide
variety of off-road applications. Specific design characteristics give them
higher centers of gravity than ordinary passenger cars.
Utility and four-wheel drive vehicles arenotdesigned for
cornering at speeds as high as passenger cars any more than
low-slung sports cars are designed to perform satisfactorily under
off-road conditions. Avoid sharp turns or abrupt maneuvers in these
vehicles.
4WD operation is not recommended on dry pavement. Doing so could
result in difficult disengagement of the transfer case, increased tire wear
and decreased fuel economy.
CONTROL-TRAC AUTOMATIC FOUR-WHEEL DRIVE SYSTEM
(IF EQUIPPED)
The 4WD system uses all four wheels to power the vehicle. This
increases traction, enabling you to drive your 4x4 over terrain and road
conditions not normally traveled by two-wheel drive vehicles.
Power is supplied to all four wheels through a transfer case that allows
you to select a four-wheel drive mode best suited for your current
driving conditions.
Driving
152

Never connect any trailer lighting to the vehicle's taillamp
circuits, because it may damage the electrical system resulting in
fire. Contact your local Ford dealership for assistance in proper trailer
tow wiring installation. Additional electrical equipment may be
required.
Using a step bumper
The rear bumper is equipped with an integral hitch and requires only a
ball with a 19 mm (3/4 inch) shank diameter. The bumper has a 1 590 kg
(3 500 lb.) trailer weight and 159 kg (350 lb.) tongue weight capability.
Use a frame-mounted weight distributing hitch for trailers over 1 590 kg
(3 500 lb).
Driving while you tow
Do not drive faster than 88 km/h (55 mph) when towing a trailer.
Speed control may shut off if you are towing on long, steep grades.
When towing a trailer:
²Use a lower gear when towing up or down steep hills. This will
eliminate excessive downshifting and upshifting for optimum fuel
economy and transmission cooling.
²Anticipate stops and brake gradually.
Exceeding the GCWR rating may cause internal transmission
damage and void your warranty coverage.
Servicing after towing
If you tow a trailer for long distances, your vehicle will require more
frequent service intervals. Refer to your Scheduled Maintenance guide
for more information.
Trailer towing tips
²Practice turning, stopping and backing up in an area before starting on
a trip to get the feel of the vehicle trailer combination. When turning,
make wider turns so the trailer wheels will clear curbs and other
obstacles.
²Allow more distance for stopping with a trailer attached.
²The trailer tongue weight should be 10% of the loaded trailer weight.
Driving
166

When lifting a plastic-cased battery, excessive pressure on the
end walls could cause acid to flow through the vent caps,
resulting in personal injury and/or damage to the vehicle or battery.
Lift the battery with a battery carrier or with your hands on opposite
corners.
Keep batteries out of reach of children. Batteries contain sulfuric
acid. Avoid contact with skin, eyes or clothing. Shield your eyes
when working near the battery to protect against possible splashing of
acid solution. In case of acid contact with skin or eyes, flush
immediately with water for a minimum of 15 minutes and get prompt
medical attention. If acid is swallowed, call a physician immediately.
Because your vehicle's engine is electronically controlled by a computer,
some control conditions are maintained by power from the battery. When
the battery is disconnected or a new battery is installed, the engine must
relearn its idle and fuel trim strategy for optimum driveability and
performance. To begin this process:
1. Set your parking brake.
2. Put the gearshift in P (Park), turn off all accessories and start the
engine.
3. Let the engine idle for at least one minute.
4. The relearning process will automatically complete as you drive the
vehicle.
²The vehicle may need to be driven 16 km (10 miles) or more to
relearn the idle and fuel trim strategy.
²If you do not allow the engine to relearn its idle trim, the idle quality
of your vehicle may be adversely affected until the idle trim is
eventually relearned.
If the battery has been disconnected or a new battery has been installed,
the clock and the preset radio stations must be reset once the battery is
reconnected.
Maintenance and care
207

WHAT YOU SHOULD KNOW ABOUT AUTOMOTIVE FUELS
Important safety precautions
Do not overfill the fuel tank. The pressure in an overfilled tank
may cause leakage and lead to fuel spray and fire.
If you do not use the proper fuel cap, the pressure in the fuel
tank can damage the fuel system or cause it to work improperly
in a collision.
The fuel system may be under pressure. If the fuel cap is venting
vapor or if you hear a hissing sound, wait until it stops before
completely removing the cap.
Automotive fuels can cause serious injury or death if misused or
mishandled.
Observe the following guidelines when handling automotive fuel:
²Extinguish all smoking materials
and any open flames before
fueling your vehicle.
²Always turn off the vehicle before
fueling.
²Automotive fuels can be harmful
or fatal if swallowed. Fuel such as
gasoline is highly toxic and if
swallowed can cause death or
permanent injury. If fuel is
swallowed, call a physician immediately, even if no symptoms are
immediately apparent. The toxic effects of fuel may not be visible for
hours.
²Avoid inhaling fuel vapors. Inhaling too much fuel vapor of any kind
can lead to eye and respiratory tract irritation. In severe cases,
excessive or prolonged breathing of fuel vapor can cause serious
illness and permanent injury.
Maintenance and care
213

Running out of fuel
Avoid running out fuel because this situation may have an adverse affect
on powertrain components.
If you have run out of fuel:
²You may need to crank the engine several times before the system
starts to pump fuel from the tank to the engine.
²Your ªCheck Engineº light may come on. For more information on the
ªCheck Engineº light, refer to theInstrumentationchapter.
Fuel Filler Cap
Your fuel tank filler cap has an indexed design with a one-eighth turn
on/off feature.
When fueling your vehicle:
1. Turn the engine off.
2. Carefully turn the filler cap counterclockwise 1/8 of a turn until it
stops.
3. Pull to remove the cap from the fuel filler pipe.
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 ªService Engine Soon/Check Engine ª 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 and reinstall it
being careful to align the cap properly.
If you must replace the fuel filler cap, replace it with a genuine
Ford or Motorcraft part. The customer warranty may be void for
any damage to the fuel tank or fuel system if a 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.
Maintenance and care
216

If you do not use the proper fuel filler cap, the pressure in the
fuel tank can damage the fuel system or cause it to work
improperly in a collision.
Fuel Filter
Your vehicle is equipped with a fuel filter that is mounted on the
underbody.
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.
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 ªOwner Guide.º 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.
Maintenance and care
217