The problem is not with the guage but with the fuel sending unit located in the trunk. I replace mine and it does the same thing. With the tank full the guage is fine. However, as soon as it hits 1/2 way mark then it starts to jump back and forth. Replaced the fuel sending unit it and the guage still bounces around. Tried to take it apart but I can't find any points to open it up. Several people have said it here that they took the fuel sender unit apart and cleaned it and it helped but I decided to live it.