For a while, my gas tank (I think it't the tank..)  has often  made a
metallic thumping sound,  shortly after startup,  and then a couple of
minutes after I have parked, and turned the van off.  I have thought that it
was just the tank contracting when the fuel pump came on,  and then
uncontracting.  Since I have noticed no other gas tank relatied problems, I
have just left it the way it is.  Sometimes it makes the same sound when I'm
filling the tank,  which dosen't alarm me too much either.  Should I be more
concerned about this?  If it can be fixed,  should it be fixed?  I have
noticed no change in gas consumption, or any other sign that something is
wrong.  Anyone else had this experience?

  Rob & 90Gl "Thumper"