Is this another fuel gauge ground issue??

[Dead Parrot]

That is the normal full reading spot +/- a couple of needle widths. My original factory gauge would stay there for about 4~5 gallons usage. It would then fall fairly quickly to just under E. At that point I had about 3~4 gallons remaining in the tank. Since I had dual tanks, no worries about running one dry as long as I was sure the other was full. Both tanks reacted about the same. When that gauge developed the rapid bounce issue, I replaced it with a Pull-a-Part find. That gauge starts dropping far earlier as gas is used and when it reads E, I will be switching to the full tank fairly quickly.

The normal 'lost ground' place for that style gauge is pretty much 3 o'clock or parallel with the line of Unleaded Fuel text.