Hello! A couple of months ago I changed the fuel pump , it really did not need another one, I thought it was the fuel pump giving me problems but it was not. It was electrical, some wires were all rusted. This a 2002 hyundia accent. Any how after I install the fuel pump it had a humming noise, which I just let that go. Now the check engine light is going on and I was told its not a senser of any kind. The motor will start missing a little I noticed when the gas amount in the gas tank goes below 1/4 of a tank, when I put more gas at least over 1/2 a tank the car runs good no missing. Why would it do that.

Have a scan done to determine which codes are stored in the computer. Post them here and we can point you in the right direction.