The regulator is a possibility but most problems with these ox66 motors have been related to the high pressure electric fuel pump get weak or quitting all together. Only other thing I can see related to a pressure drop when running is voltage at idle. I would be very careful running this wide open until I found the problem.
ï¿½The world will not be destroyed by those who do evil, but by those who watch them without doing anythingï¿½ Remember what He has done and remember that He is not done yet! GOD IS GOOD