Well I did it! Went to the junkyard to do some research and found a
number of fuel senders hanging out of old XJ'a and a couple still in
the tank. removed three of them, 2 still had new looking pumps. I
bought a sender and a complete set up for $49 and went home to test
these that were both pulled from a 90 and an 88 XJ.

Success! The Fuel Gauge worked.

Now I needed to unisnstall mine and see what was up. Luckily the
practice at the yard helped a ton!

As I am pulling it out I noticed that the plastic housing of the sender
unit is disconnected from the fuel sender metal body. As I was
extracting the whole unit from the tank the filter boot fell in the
tank! Damn! Hands too big to get in fuel pump hole. Lower the tank to
get it out.

Few hours later...after testing it a few times.....reinstalled and
voila....gauge works!

Thanks for all of your advice,

LTK