Noise from gas tank

[eraseraj]

ok, when my jeep grand ltd. 4.0L was at idle the other day, i walked behind it to get something and heard a noise comming from the gas tank. It sounded as if a ball was rolling around in the tank, has any one ever heard this noise before and know what it is?

I feel that death is comming to my jeep once again!!!

[eraseraj]

Found out today that it may be the fuel pump making the noise. Has anyone ever heard of a fuel pump making noise when it gets old?