Fuel pump sending unit needs to be replaced in the Gas Tank. Big Fix by a Qualified technician. I believe you have to replace the whole fuel pump assembly unit.
More than likely the fuel gauge sending unit located in the fuel tank is faulty.
Most Likly a fuel sender problem
Depends on the car. Most should drop to empty when the ignition is off but some cars stay in the same position, they are rare though. (Toyota crown, Isuzu panther)
The float that tells your gauge how much gas you have may be stuck or there is a problem with the system that sends that information to the gauge.
Looking from the rear of the gauge apply +12v to right terminal and ground to left terminal. If functional the gauge will go to full. Reverse wires and the gauge should go to the left below empty. If it does these two things the gauge is working and the problem is wiring or sending unit. Randy Nix
this is a problem with the gauge cluster. very common problem. you may also notice the neeedles moving very erratic at times. it is a common problem with s10/jimmy/blazers/sonoma
With the thermostat.
The floater inside your pump is sticking. You will have to replace your fuel pump in order to fix this problem.
The fuel gauge sending unit in the fuel tank is probably the problem.
gas gauge sticks either full or empty This is a known problem with Chevy's that they will not recall on. I had same problem with my 2000 Blazer. Had to replace fuel pump / gauge assembly in tank. It took a couple of hours to do, but was worth the headache having a gauge that works now, No more running out of gas or watching mileage.
My 2001 had the same problem. There is a GM recall to replace the sending unit.
Its probably the float in the gas tank that tells how much fuel is left in the tank... its sticking.