Check the wire going to the fuel cut valve, it is a one wire valve as it is case grounded. If you have dealer software you can command the valve on and install a test headlamp and verify it is getting good power. The valve essentially opens to allow fuel to the 7th injector. If the computer sees an issue it can use this valve to cut off the fuel supply to the 7thn injector. I have seen sevral P0005 codes but never a P0007. Is it possible you unplugged it during testing? If not see the attached service bulletin. Let us know how you make out.