Hello I am not sure where to start since I am new to this, so I will just get to the point. I have a 2000 F150 4x4 5.4L the check engine light came on one day while I was driving and it felt as if it were gonna die. I went to Auto Zone where they scanned for the code and it said Cyclinder 3 misfire. So I bought a new plug and coil. My boyfriend replaced the plug and coil, but the truck is still missing. We thought maybe there could be some water in the fuel, so I bought some Heet, and put it in the gas tank. Still the service engine soon light is on and it is still missing. I am not sure what I should do now. I am open for any suggestions that anyone has. Also does anyone know what the fuel pressure for my truck should be? Boyfriend is thinking maybe it could be the fuel pump. Thanks!