Thanks 80s Tech! That is exactly what I think the issue is. I am sure that the noise is coming from the very top of the tank where the pressure release valve is. And I was under the impression that the fuel pump is before the fuel filter/pressure regulator so the residual fuel pressure would be held between the pressure regulator of the fuel filter and the pressure relief valve on the siphon jet assembly. Since I recently replaced the fuel filter/regulator, the only other pressure point would have to be the fault relief valve.