hopefully its not the pump because that can get spendy. i had a similar problem after my gas tank swap..turns out this guy came un-clipped
just popped it back in and been good since. it had been in with one clip the whole time so thats why it popped out but both snapped in the 2nd time.
bad news is you gotta drop the tank to check, but its not that bad of a job..just make sure you are close to E when you drop it.