* Check the owner's manual: This is the most reliable source.
* Look inside the fuel filler door: The capacity is often printed there.
* Check the sticker on the driver's side doorjamb: This sticker often lists the vehicle's specifications, including fuel tank capacity.
Without more specific information about your particular 2004 F-150 (engine size, cab style, bed length, etc.), it's impossible to say definitively.
