f250,2007,6.0 diesel, 42,000 mi. On three occasions in the last 30 days my truck won't start when warm. It cranks fine but engine won't catch, eventually it will start but this last time it ran sluggishly as if the timing isn't advancing. The problem seems to me to be electrical in nature,perhaps a sensor or computer problem. I am not a diesel person and am lost on new vehicle electronics. It doesn't smoke or have any other problem. I have seen others with similar problems but no definitive answers.