I have a 1997 Sierra that has had an on-n-off fuel gauge issue. I'm aware of the sending unit issue from reading other users' posts. Mine is different, believe it or not. The gauge has begun to have a mind of its own. When the engine is running, it will spin erratically, then rest momentarily on the correct fuel level, then start spinning again. Sometimes it will stick on the needle below it (oil gauge, I believe) then start spinning again. Could this be a connection issue behind the cluster? Or am I looking at the sending unit?