There may not be anything wrong with the gauge. The manufacturer may have switched to a modern non-spring armature.
The old style movements had a tiny spring that pulled the pointer to empty, when power was added the magnetic field pulls against the spring and holds the pointer at tank level.
The newer movements (which have been used in cars since the 80's) do not have a spring. They work on a balanced magnetic field and have very low friction bearings. The armature moves when the magnetic field has a value + or - relative to where the pointer is currently at. When the power is off the pointer just stays where it is. You can see your tank level without turning the key on.
The new movements last longer and are less likely to stick.
