Knocking under my vehicle

[neald]

My fuel pump went out about a week ago and now underneath my vehicle something has started knocking and it sounds like it is coming from a black case that runs from my back axle to my drivers seat.

 

[uxb101]

did you do the pump or did you get it done at a shop or stealership??? take it back to whoever did it ,dosnt sound right, its gas dont mess with gas you go boom-boom