I thought I would give an update on what I found. After talking to hotline I checked the maf and exh back pressure. They both checked okay. However, on test drive I found two cyl dropping out under load. I then decided to remove valve covers and check for leaks. I did not find a leak in fuel system. I replaced the two inj, blead system and retested for fuel leaks and passed. I returned to costumer and asked him to bring it back in 1500 miles to check oil. After giving back to costumer I went to a training class and talked to the instructor. He suggested to remove all eight inj and install them facing up, unplugged and crank the eng over and look for fuel leaking.