The fuel gauge is fine for the first 50 miles or so but then it keeps going up and down. The needle will be at 1/2 tank one minute and 1/4 tank the next, and then it will go back up to about a 1/2 tank. It does that even when Im going down the highway so it isnt that the fuel is moving that much in the tank. Any ideas on how to solve the problem or what needs to be replaced? Im getting tired of having to guess how far I can go before I run out of gas.

Any ideas on what needs to be fixed?

Probably need to replace the tank sending unit.

Replacing the sending unit will definitely fix it, but I was able to repair mine by simply disassembling and cleaning it. Have to remove the tank though

The sending unit is nothing more than a float arm on a potentiometer, that should read 90-100 ohms at full, and close to zero ohms at empty.

As the slider gets corroded, the resistance will go up in certain spots, causing the gauge to read full or past full when it's really not.

It's really easy to disassemble the SU once it's out of the tank, just bend the metal tabs out and pull it apart, and clean it out with some contact cleaner or alcohol on a toothbrush. The metal tabs broke on mine though, I had to solder it back together

How difficult is it to remove the gas tank?

Does the tank have to be empty to be removed?

A will yield plenty of information.

It's harder than changing the oil, easier than solving world hunger. The less gas in it, the easier the tank is to handle.

If I take it out could I swap it with a 4th gen tank?

I heard they are plastic so I was thinking it might save some weight since the 3rd gens are metal.

Any thoughts on that?

I had the same problem and i swapped ot the gauge and it is a lot more steady now

honestly the plastic tank is about just as heavy as the stock steel

the steel is very thin and the plastic one is pretty thick
only differance really is the 4th gen one wont rust

No rust = good