Why is my fuel gauge in my 96 grand chreokee laredo keep going from empty to full?

I am in the process of fixing my fuel gauge problem now. I took the fuel pump out of the tank. at the top of the float arm there is a memory stick much like the sim card you install in your cell phone. it has many copper lines running through it (looks like the gas gauge) and the read needle on your float arm gives the reading of how full the tank is. the needle on the float arm seems to rock back and forth or side to side which over time pulls the needle which is spring loaded (no actual spring, but by the bend in the metal) away from the chart or sim card. you can try very very gently to put the spring back in the needle by inserting a small regular screwdriver or equivalent behind it and try and get the needle to make contact with the sim card again. if successful your fuel gauge should work properly again and you save a couple of hundred bucks.