Fuel gauge fault reading

[drmagieed]

the fuel gauge when the tank is full, it is right and went to full mark then starts to go down rapidly and stops on empty mark although the tank is a half load. I changed two new OEM sender units and the problem is still there.
what are the possible solutions for that. Aveo 2009 LS

[drmagieed]

are there any reason or solution for that?