Fuel gauge moves back and forth from full to empty

You could use two resistors, Two different ohms specs for full and empty. Place resistor between proper wire colors in diagram. Turn on the key, If gage reacts properly to full and empty resistors, then I think the problem is the sending unit in gas tank. If not, the problem could be almost anywhere, wiring circuit--pcm--instrument cluster. I did see trouble codes relating to fuel gage sending unit. I hesitate to get into that? good luck

Sounds like a faulty sender unit in the fuel tank...

If your fuel gauge is showing you in accurate readings this is normal to all vehicles that are not used to fill-up gas full regularly but sometimes the cause of the inacuracy is due to faulty float valve in the gas tank you need to replace it

This problemis always caused by a defective fuel level sensor. The level sensor islocated of course in the gas tank. To change the level sensor you must remove the gas tank from the truck.

The problem lies in the sending unit in the tank. It could have a wiring problem or the sending unit is bad.

It sounds like the fuel sender is bad in the fuel tank.

Adam, I like your solution, but this is easier:
1. Get a strong magnet
2. Use the magnet to move the needle into the top half of gage (don't take anything apart)
3. Test it by turning the car on.

probably you got a problem with your fuel gauge sender that goes inside in the fuel tank, that sender is only a coil that works together with a fuel lever,if you want to save some money buy it separate from the fuel pump.

it sounds like the level sensor on the sender (fuel pick up pipe in the fuel tank) is getting stuck. the level sensor is a float that is attached to the sender, and you will need to remove the fuel tank to get to it.

hope this helps.

If you remove the sending unit in the gas tank, move it manually by hand as u saw done earlier, the gauge on the dash should also move. As long as the sending unit in the tank isn't 'stuck' at the half full level, the gauge should register empty to full as it moves. To be honest, I'm not sure if I would bother taking the sending unit out. 1st, u must be very careful not to blow yourself up when working on the gas tank (no sparks, etc), all u really need to do is fill up your car, see how many miles a tank of gas will go (carry a can of gas with u to see how many miles before u run out). If it's 350 miles, just set the trip gauge to zero every time u fill up, and get gas every 300 miles so u don't run out. If the sending unit moves freely, everything (wiring ) is connected properly, then it probably is the fuel gauge. good luck!