Gas gauge quite working so went to replace sending unit and found something in the gas tank. Its steel - looks like a tank in my tank - best I can describe it. I can move it around in the tank with a screwdriver or magnet. I ***ume its some sort of baffle that has come loose. Is there some sort of shroud that protects the float arm? I'm guessing theres a new tank in my future but it has me stumped