You first need to discover what is wrong. It can be the gauge, the sending unit (the part that measures the gas in the tank), or some associated wiring.
Change your fuel sending unit.
If the fuel gauge is stuck, the needle never moves, then the gauge has a problem and needs to be replaced.
either the fuel gauge needs replacing or the fuel gauge sending unit in the fuel tank is stuck
check for broken wire from fuel sender unit in fuel tank to gauge. check fuel sender unit for proper operation. float may be stuck in the tank then check fuel gauge
The 1997 Ford Explorer fuel gauge can be stuck on fault because the fuel float is malfunctioning in the fuel tank. The fuel gauge fuse might be blown.
The fuel gauge on a Chevy may become stuck if the sending unit is defective or become disconnected. Without a signal from the tank, the gauge will not move.
A common problem with Honda cars is that the fuel gauge is stuck on full. This problem is solved by replacing the gauge cluster.
If the fuel gauge isn't working on a 1999 Chevrolet Blazer it could possibly be because the float is stuck in the fuel tank. I had this problem when I got my 99 blazer, the float and sensor for the fuel gauge is on the fuel pump which is in the fuel tank to keep it temperature regulated. I had to replace my fuel pump, which ended up going bad on me, and after it was replaced the gauge works just fine.
The float is stuck. Try a fuel cleaner or additive.
Sounds like the sending unit in the tank is stuck. It works kind of like the float in your toilet. There is a piece that floats on the top of the fuel and it is attached to a rod that goes to your sending unit. The higher the float, the more gas is shown on the gauge due to the position signal the sending unit is sending out to the fuel gauge. If it is stuck, it probably is best to have it replaced.
fuel sending unit broken wire or gauge is bad
More often than not, a fuel gauge problem is usually a faulty fuel gauge sending unit in the fuel tank.