So when I went to turn on my truck today it showed that I had half a tank but when I was driving it around yesterday I only had below a quater tank, could this be a problem with something where its not reading right?

The only thing that I can think of is when I take off my gas cap the little metal that is supposed to cover the gas cap is halfway off, could I be losing more gas this way?? Thanks for any help!!

 

*the little metal that is supposed to cover the gas hole

 

Mine does this thing where it gets stuck around half a tank. Only way to get it to reset is to turn off the truck and then turn it back on.