FUEL GAUGE SHOWING FULL TANK BUT BUT ONLY HALF TANK OF GAS

depending on your year, make and model. most are located in the fuel tank with the electric fuel pump.

If the trouble with the gauge started after you worked on it then you likely damaged or created a restriction to the movement of the sending unit. You will have to remove the tank and double-check your work.

You will need to replace the fuel tank level sending unit.

have the fuel sender unit checke( ground or loose wires) / replaced

Float is off. Just try to put a full tank of gas in it and watch the gauge. Noone can siphone your tank BC there is a ball before the tank abling u not to siphoned.

The fuel sender is in the tank and is part of the fuel pump module ( all in one). the fuel sender is a rheostat and is like a dimmer switch in you home to dim lights, the higher the level of fuel the more voltage the computer sees hence the lower the fuel the lower the voltage it sees. With the age of the car this is likely the problem. But there is a part in the instrument cluster that reads this voltage and sends power to the gauge intermittently. In older cars it was called a anti slosh module. It was there because as the car went up and down a bumpy road the gauge would read erratically. the cost can be prohibitive to fix this but if you can live with it i would. If not expect to spend 600 dollars or more to trace it down and fix it.

the problem is caused by a defective gas gauge sending unit, this part is located inside the gas tank, you must remove the gas tank to replace it.

Unfortunately......you have a gas sending unit that has failed....and yes it is located in the fuel tank...these GMs have had a very notorious tsb for the fuel tank pump and unit assembly failing due to design.....theres nothing you can do to repair this ....but you can replace this unit.....it's kind of a bear with a full tank of gas if you're gonna be doing this yourself....on the ground...this fuel tank pump unit is found quicker and more reliably at the dealership. ...HOPE I HELPED!!!!!

well the gage is made of rubber it could be sticking no other way than to replace the gage itself/ please rate my response thank you very much

you have a bad sending unit inside your tank.
the resistance of the potentiometer inside is broke on the half tank part.

you have to replace it.

tnx 4 using fixya.

drcool