Hyundai Repair: Fuel System, volt meter, fuel level

Question
I have a 1999 Elantra, when the fuel in the tank gets to 1/4 the engine is being starved for gas. If if fill the tank the the problem goes away.  I have replaced the filter and fuel pump.  This did not fix the problem.

Answer
Are you sure the gage is reading right an not off.. you need to take out the sending unit an check that its reading right with a volt meter from full to empty an then check the gage,
fuel level empty              1/2       full
angle      -40%               0%      +40%
tolerance  +or -2.5      +or-5   +or-2.5
resistance
in ohms  95                32.5        7