Ford Expedition Owner's Manual page 201

It is best not to alternate repeatedly between gasoline and E85. If you do
switch fuels, it is recommended that you add as much fuel as
possible—at least half a tank. Do not add less than five gallons (18.9L)
when refueling. You should drive the vehicle immediately after refueling
for at least 5 miles (8 km) to allow the vehicle to adapt to the change in
ethanol concentration. If you exclusively use E85 fuel, it is recommended
to fill the fuel tank with regular unleaded gasoline at each scheduled oil
change.
Octane Recommendations
87
(R+M)/2 METHOD
particularly in high altitude areas. Fuels with octane levels below 87 are
not recommended.
Do not be concerned if your engine sometimes knocks lightly. However, if
it knocks heavily under most driving conditions while you are using fuel
with the recommended octane rating, see your authorized dealer to
prevent any engine damage.
RUNNING OUT OF FUEL
Avoid running out of fuel because this situation may have an adverse
effect on powertrain components.
If you have run out of fuel:
• You may need to cycle the ignition from off to on several times after
refueling to allow the fuel system to pump the fuel from the tank to
the engine. On restarting, cranking time will take a few seconds longer
than normal.
• Normally, adding 1 gallon (3.8L) of fuel is enough to restart the
engine. If the vehicle is out of fuel and on a steep grade, more than
1 gallon (3.8L) may be required.
• The service engine soon indicator may come on. For more information
on the service engine soon indicator, refer to the Instrument Cluster
chapter.
See Settings in the Instrument Cluster chapter for information on
calculating DTE (Distance to empty).
2013 Expedition (exd)
Owners Guide gf, 1st Printing
USA (fus)
Fuel and Refueling
"Regular" unleaded gasoline with a
pump (R+M)/2 octane rating of 87
is recommended. Some stations
offer fuels posted as "Regular" with
an octane rating below 87,
201