ORIGINAL: bruce88123
Skynyrd Man-
need to remove tank if necessary and find out what it is. Are you sure you are not hearing the "CLUNK" inside the tank moving? Do you know what a klunk is? Not to be insulting, I just don't know your knowledge level. Remember tank orientation when removing so you can put it back same way. Mark with Sharpie or something if needed.
Something to do with keeping a steady gas flow?
I think you are right, I forgot about that item till you mentioned it. I read something about it a while back.