After testing the entire fuel supply system the problem turned out to be loss of residual fuel pressure. Tested fuel pressure which was 92psi normal but was dropping to 45psi a little too low, and then suddenly to almost zero within 20 seconds. Tested the FP accumulator and FP regulator both tested good. Since the pressure drop was sudden I replaced the check valves on the fuel pumps. That did not help at all. So there was only one thing left and that was the fuel injectors. Replacing the fuel injectors solved the problem. Thanks everyone for all the great advise.

Dave.