84 gas gague problem

[hatzie]

This is not a bad or loose sender ground.
The fuel sender is a variable resistance to ground from 0-90Ω. The fuel sender does not get power it's a passive component.

0Ω resistance through the sender makes the gauge read Empty on the gauge and 0Ω on the sender wire is a dead short to ground.
The needle randomly swinging to E means the sender wire is chafed or pinched and intermittently grounding out to the body or frame somewhere along its' run between the sender and the fuel gauge itself.

In contrast 90Ω is Full and more resistance than that drives the needle toward the 3:00 position. A completely open connection is higher resistance than 90Ω.
This is not a loose sender connection. Loose, corroded, and completely open connections cause the needle sweep to shift toward the 3:00 position. A corroded sender clip in the cluster could make the gauge read 1/8 when the tank is stone empty but it would not drive the needle toward the E position.