Long story short:
Fuel tank read empty. I filled it up to the brim, but it was only 7.5(US gallons). Fuel tank spec says it's 9.9US gallons.
Looks like my fuel tank sending unit's a bit pessemistic. I hear a knocking sound when it's low on gas.
Did my fuel float get filled up, thus rendering a too-low reading? Shame if it is, since I replaced it new about 6-7 years ago.