FORD 2010 Crown Victoria v.1 - Manual (Page 247)

WARNING: If you do not use the proper fuel filler cap,
excessive vacuum in the fuel tank may damage the fuel system
or cause the fuel cap to disengage in a collision, which may result in
personal injury.
FFV (Flex Fuel Vehicle) fuel cap
If your vehicle is FFV capable, it will have a yellow colored fuel cap.
Crown Victoria vehicles only
Choosing the right fuel
If your vehicle is a flexible fuel vehicle (FFV), use only UNLEADED
FUEL and FUEL ETHANOL (Ed75–Ed85).
If your vehicle is not a flexible fuel vehicle (FFV), then only use
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.
Cleaner air
Ford endorses the use of reformulated “cleaner-burning” gasolines to
improve air quality, per the recommendations in the Choosing the right
fuel section.
Maintenance and Specifications
247
2010 Crown Victoria (cro)
Owners Guide, 1st Printing
USA (fus)