I just purchased a 2005 f350 with the 6.0. It cranks for 4-5 secs before starting. Once started, it runs great, and when at operationinformation temp, it starts perfectly. Batteries tested weak, so I replaced them both. FICM tested and good. I apologize If this has been asked and answered before, but I am almost cross eyed from reading, and I can't find anything describing my problem.