LLY will start fine but after a few minutes of drivng it acts like it's in limp mode. White smoke pours out. Knocks super loud like a older powerstroke. I pull over and shut off. Wait about a min and restart. Runs great for maybe 5-10 min then losses power again. Is this a computer problem? I replaced theFuel filter and have fresh fuel in it. I also removed the banks tuner and it still does this. Injectors maybe? Thanks for any help.