fuel gauge folly

I put in a new Chrysler type Equus fuel gauge over winter (tank was filled in fall). The old gauge had been sitting a E regardless of fuel level. New gauge reads Full, but after some driving it seems to not be dropping..I see it bounce around in turns or quick stops...I'm still hoping it's working but am doubtful. I did tests in fall showing gauge was bad and have no reason to think the sending unit coincidentally went bad at exact same time. ..Will burn a couple gallons today and know for sure I guess. Anyone had this situation?