This discussion of road noise and possible fuel pump sounds and other sounds heard in the car is a bit bewildering. It seems unless we are in RD's car or anyone else s it is hard to determine. RD, when I sound out what you say you are hearing: it sounds a lot like a resonance that I hear when I am going over a rough surface...its like a high pitched vibration being set up by something in the car....but for me, at least, this resonance seems to be coming from further forward than the back end.
I do know that this "resonance" that I hear is also very annoying but I don't know what to do about it either......... And is this the same thing RD is hearing; I have no idea.........