Fuel Level Input (FLI)
WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 2007 Mercury Mountaineer, 2007 Mercury Monterey, 2007 Mercury Montego, 2007 Mercury Milan, and 2007 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
The FLI is a communications network message. Most vehicle applications use a potentiometer type FLI sensor connected to a float in the FP module to determine fuel level.