I realize this topic is pretty old, but I just dealt with this myself recently so I have some comments.
Under your hatch sound proofing mat, by the right wheel, you should see a little grey box:
This box is what converts the analog signal from the sender to digital for the GLL dash, though strangely not all digital Z's seemed to have it. IF you have this box, and it's still working, the analog fuel sender should work for you. I recently picked up the revised sender from Courtesy Nissan: https://www.courtesyparts.com/oem-parts ... aXNzYW4%3D
and it's working fine with my digital dash. The "discontinued" GLL model of the fuel sending unit was actually the exact same unit, but it also came with an updated signal converter box. If a new fuel sender doesn't clear up your problem, then it's possible your signal converter box is the issue and those are long gone, so you'd need to try and repair your existing one.