What causes the fuel gauge to show less than full when the tank is actually full?

[RiverLynn]

Reasons why the fuel gauge shows less than full when the tank is actually full: 1. There may be an issue with the fuel level sensor, usually caused by poor contact. Check whether the fuel float can send normal signals. Remove it and move the float to the highest position to see if the fuel gauge indicates full. Determine whether the fault lies with the gauge or the float and replace accordingly. 2. The fuel gauge may be inaccurate. Check if the instrument circuit has been modified. Visit a 4S shop to verify whether the gauge pointer can reach the maximum line and if the indication is accurate. 3. The fuel gauge pointer may be stuck, in which case the entire instrument must be replaced. Gasoline is a volatile, flammable hydrocarbon mixture liquid obtained from petroleum through fractionation, cracking, or pyrolysis, and it is used as fuel.