FORD 2010 Flex v.1 - Manual (Page 364)

immediately. It may take several driving cycles for the check fuel fill inlet
lamp or CHECK FUEL FILL INLET message to turn off. A driving cycle
consists of an engine start-up (after four or more hours with the engine
off) followed by city/highway driving. Continuing to drive with the check
fuel fill inlet lamp or CHECK FUEL FILL INLET message on may cause
the service engine soon lamp to turn on as well.
WARNING: The fuel system may be under pressure. If you hear
a hissing sound near the fuel filler door (Easy Fuel™ “no cap”
fuel system), do not refuel until the sound stops. Otherwise, fuel may
spray out, which could cause serious personal injury.
Choosing the right fuel
Use only UNLEADED fuel or UNLEADED fuel blended with a maximum
of 10% ethanol. Do not use fuel ethanol (E85), diesel, methanol, leaded
fuel or any other fuel. The use of leaded fuel is prohibited by law and
could damage your vehicle.
Your vehicle was not designed to use fuel or fuel additives with metallic
compounds, including manganese-based additives.
Note: Use of any fuel other than those recommended may cause
powertrain damage, a loss of vehicle performance, and repairs may not
be covered under warranty.
Octane recommendations
3.5L V6 engine
Your vehicle will run normally on 87 octane regular fuel. Premium fuel
will provide improved performance.
3.5L V6 EcoBoost engine
Your vehicle is designed to run on regular fuel with an octane rating of
87 or higher. For best overall performance, premium fuel with an octane
Maintenance and Specifications
364
2010 Flex (471)
Owners Guide, 1st Printing
USA (fus)