The fuel sending unit is located on the top of the gas tank. Look in your trunk, pull up the carpet and you should see an access panel near the back seats. Its usually a silver shiny metal cover with wires running through it. If you don't find it there it may be under the bottom cushion of the back seat. This could be part of a faulty fuel pump also because the fuel pump is located and accessed at the same place. I suggest testing the fuel pump(checking the pressure on the fuel rail using the proper tools) to see if the fuel pump is working correctly.