I can't believe that it is time once again to replace the fuel sending unit on my truck. I did this about 18 months ago.

I am assuming that it is the sending unit. It started by slowly registering the correct levels and then stopped registering all together and decided to park itself at the 3/4 mark. Full or empty it reads 3/4 of a tank. With the ignition off it reads zero and back up to 3/4, key on.

Is this another sending unit problem or perhaps something else?