Another gas gauge problem

If you want to avoid pulling the cluster, you can test things at the kick panel connector. On the dash side connector terminal 1, connect different resistors to ground to simulate what the fuel sender does, and verify that your dash gage works correctly. On the body side, measure the resistance from terminal 1 to ground to see what the fuel sender is doing. Smart to replace the dash Vreg with an electronic one (many posts on that).