Those of you that run your truck until the fuel light comes on, you are killing your fuel pump by doing this. The fuel pump likes to push fuel instead of pulling fuel, with it in the tank it is easy to push fuel and work less, also it cuts down on the noise it makes. The fuel pump uses the fuel in the tank as a coolant, running the fuel very low lets the pump heat up and shorting it's life. With a low level in the tank the filter/sock will pick up all of the debris on the bottom and clog up, this is the only filter between the tank and injectors. Unless you like to drop the tank to replace the pump and/or filter prematurely, keep at least 1/4 tank of fuel so the pump will stay cool and live a long and happy life.