Mike:
My guess, based on it taking months for the problem to show up and the fact it registers at or near empty, is the float is leaking. The sending units have brass floats and a very large percentage of the aftermarket floats leak. When I replaced mine, it leaked as well.
When you pull the failed sending unit out of the tank, you should be able tell if the float has leaked because there will be fluid in it.
A common fix is to remove the brass float (it simply snaps in place) and replace it with a plastic float. This is such a common problem that someone has identified a suitable replacement, I believe it is a Ford part. I may have the part number at home, but a Google of the problem usually pulls it up.
Last edited by Cris; 05/02/2018 6:40 PM.
