I had the rev at shut down too.
Over on the frybrid forum, another member with a 2-tank system said that he had the rev & CEL (code 205) on shutdown, and he cured it by rearranging his fuel flow a bit.
So, being pressed for time, I replaced the SOV o-ring and rearranged the fuel plumbing at the same time. Since then, it's worked flawlessly, but I can't for sure say which fixed it.
more about the change in plumbing here:
http://jakesbenzconversion.blogspot.com/2008/04/fuel-plumbing-revisited.html