Fuel Gage Problem

Good afternoon, I've a 2000 Monte Carlo with 75K miles on it. I seem to be having a problem with a floating gas gage. It appears that the only time that my gage seems to be accurate is when i first turn the ignition on prior to cranking the engine. When cruising down the highway, i noticed that the gas gage has a tendency to float back and fort from the 1/4 reading to the full tank reading. Have any of you that own a Monte Carlo or any other chevy experienced this problem? If so, how did you fix it? Thus far, i browse the internet and found a website "www.topix.com/forum/autos/chevrolet-impal/THM0SNU6QSAKVTC2P" which has an article named "Chevrolet Impala Fuel Gage Jumps when full." Some fellow named "JMc" states that the problem is the sending unit, which is a little (generally black piece) with 3 brushes, that touch an arched panel, he goes on to state that the paned looks dark and to clean it, all you do is take a Q tip or some other small object to clean off that arch of metal which should shine it right up." He concludes by stating to make sure that the three brushes aren't bent while cleaning the arched panel. If you are familiar with a floating gas gage and know how to fix it, please let me know ASAP.