My gas gauge usually just says down, totally empty, and won't work. But sometimes it shoots up to a random amount on the gauge, the drops back down. Or the light comes on and the needle doesnt move, more just any combination of those two things. Any ideas? fuse maybe?

 

Its the float resistance. There are little fingers on the float arm that ride along the a contact board. Well the fingers create a wear line in the board where they don't work like they used to, or the fingers are too far from the board and not getting a good contact anymore. The only thing you can really do is replace the sending unit, or try to bend the fingers closer. Just be carefully there not ever strong and can break easy.
Is even possible then your fuel gauge as acting it but it sound more of in the tank issue.

 

So I'm going to have to drop my tank no matter what?

 

Pretty much. You either leave it and rely on the light or on trip mileage. Does your light even if your getting empty?

 

The lights always on because it thinks the gauge is at the bottom and out of gas.

 

Does your cluster have a trip reset. What I would do if was me full up all the way and then reset the trip and once you get around 150/200 miles. Fill it up again and then check and just relay on on your trip, or pull the pump and replace and keep to pump just in case.