The pointer will not show the level of fuel remaining in the fuel tank.?

90% of the time this is a ground issue. Mostly cause of rust. If not, you have a bad sending unit, which is in the tank. However it is a problem. The easiest way to go about this is to carry 2 gallons of gas with you at all times, so you won't get stuck on the rd somewhere. Replacing can be costly and should be done by someone that knows what they are doing. You could strike a spark and get yourself on fire, by doing this procedure of fixing it yourself.