BTW, when I went to relieve the pressure in the fuel rail nothing came out! I unscrewed the supply line and there was no pressure present. What do you think about that?[/QUOTE]

Hi Les, I had the same concern with mine. I did the leak down test that we have in the service manual to determine whether it was the check valve in the regulator; or the check valve in the fuel pump. Mine was apparently the fuel pump check valve, although I still haven't changed out the pump. Service manual says that quick loss of pressure indicates the check valve in the press. reg., and a slow loss indicates check valve in the fuel pump(this is of course after determining that it's not leaking through an injector).
It doesn't seem to be a problem for us, as it starts up OK, but perhaps it would start instantly instead of a second or two if I changed out the fuel pump. Didn't you just get a new 55 pump? Mine leaks down to near zero pressure, but holds just enough(maybe 1/2psi) to keep fuel in the lines. How long should a healthy check valve hold fuel pressure? A week, a month; I don't know.