Fuel gauge is not reading at all even though there is fuel in gas tank?

most fuel gauge readings are not that accurate anyway so its out of fuel but not what the is guage reading. but the fuel level sensor in the tank may be at fault sound like its the prob but the instument pack should put the low fuel light on if its fitted on your vehicle spec but not always fitted even though the warning light is present hope this helps

This problem usually occurs due three reasons:
1. If the odometer is reversed. (In this case the speed is not read. if meter reads speed ignore this reason).
2. The pointer in the sender fuel gauge is carbon fouled. (Remove the fuel gauge from the fuel tank and just clean the pointer. The fuel gauge is located under the rear passenger seat).
3. The fuel gauge in the fuel tank is defective.(Replace with a good known one even purchased from the junk).
Hope that works.Thank you for visiting Fixya.

If the signal from the sending unit is correct, the problem would be in the gauge on the dash.

make sure you fuel tank float isn't becoming saturated with gasoline. If the gauge reads full when it is indeed full, you probably don't have a short in the wire that goes to your fuel float sending unit. If that wire is bare and shorts out it will say you tank is empty since it works on resistance open or unplugged the gauge would read full, closed is or going to ground the gauge will read empty. I would think the float might be bad or the float arm got stuck down when you turned a sharp corner. I had one of these cars but I don't remember exactly where the fuel level sending unit is located and if you need to remove the fuel tank to gain access to the sending unit. I hope this helps you

it could be the problem with fuel tank unit, replace that.

fuel sending unit located on the fuel pump in gas tank

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Sorry to say,but the fuel sending unit is the problem,the fuel tank will have to be lowered out of the vehicle to replace the unit.If the fuel sending unit is not available by itself you will have to replace the whole fuel pump assembley.

GM had a problem with the fuel sending unit cards inside the fuel tank,If you replace that you should be good to go.

It is more likely to be the fuel guage sender which is faulty.

Usually if the gas gage does not work yes it is true it may be the sensor if it is electronicly controlled. the sncor will more than likley be in the tank. here is how to remove your gas tank.

1. Before servicing the vehicle, refer to the precautions section.
   
2. Relieve fuel system pressure.
   
3. Drain the fuel tank.
   
4. Remove or disconnect the following:
   
   • Negative battery cable
     
   • Fuel filler and vent hoses
     
   • Fuel tank skid plate
     
   • Fuel tank wiring connectors
     
   • Fuel supply and return lines
     
   • Fuel tank
     
   • Fuel pump assembly
     Fuel pump assembly mounting
     

To install:

1. Install or connect the following:
   
   • Fuel pump assembly
     
   • Fuel tank. Tighten the bolts to 27 ft. lbs. (36 Nm).
     
   • Fuel supply and return lines
     
   • Fuel tank wiring connectors
     
   • Fuel tank skid plate
     
   • Fuel filler and vent hoses
     
   • Negative battery cable
     
2. Start the engine and check for leaks.