Just went through similar issue with fuel gauge.
Gdetraier option two may knock the float loose from what every is holding it.
In my case it would stick at about 1/2 tank. The float rides on a open resistor to change fuel level.
Hitting it did not work! after draining nearly all the fuel, I was able to see movement in the fuel gauge.
I decided to fix it correctly. Took to my heavy repair facility. Resistor was rubbed to the extent it snagged the arm. Tried to get exact replacement. Parts houses said this is the one, wrong my tank is 15 inches deep, replacement is 12 inches.
Had the shop modify the complete assembly that came out of tank. New float mechanism, and most important a new fuel pump.
Tank your heart medicine as in my case expensive! Trace over $1000.