My 04 Duramax has just started this. When it is cold it will start fine run for around 5 sec. then dies. We took it to a local repairman and he told us it needed new fuel injectors, but we haven't lost any power. We then took it to a dealer and it never did it again and they couldn't find anything after being their for a week. Now about 3 weeks later it is doing it again. If you turn the key on and of to let it cycle it starts fine and stays running. My question is is it the glowplugs.