Ffv (Flex Fuel Vehicle) Fuel Cap; Choosing The Right Fuel - Ford 2007 Crown Victoria Owner's Manual

5. Turn the filler cap clockwise 1/4 of a turn until it clicks at least once.
If the Check Fuel Cap indicator or message comes on and stays on after
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 vacuum in
the fuel tank may damage the fuel system or cause the fuel cap
to disengage in a collision, which may result in possible personal injury.

FFV (Flex Fuel Vehicle) Fuel Cap

If your vehicle is FFV capable it will have a yellow colored fuel cap.

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. Your vehicle was not designed to run on E85 fuels that are
blended with a maximum of 85% ethanol. Do not use fuel containing
methanol. It can damage critical fuel system components.
2007 Crown Victoria (cro)
Owners Guide (post-2002-fmt)
USA (fus)
Maintenance and Specifications
241