I have owned my 2006 F250 6.0 litre diesel for about 18 months now and it has been running like a top, very impressed with the power.
I was out in the bush last week, my wife started up the truck to hook up the trailer. We shut it down while we packed up our gear when I tried to restart it I got a very light start and very low idle. I pushed in the accelerator and the engine revved up. I shut it down and tried a restart with the same results, pushing in the accelrator resulted in nornmal idle. I let the engine warm up and then continued deeper into the back country.
The next morning I had a normal start and drove for about 10 miles. I shut the truck down for about 5 minutes and when I tried starting again I got the same light start. pushing the accelerator had no effect. the engine then died. I tried a few more attempts the engine would run (lightly for a few seconds then quit.) I let it sit for about 30 minutes to no avail.
It seemed like fuel starvation to me. I checked out the fuel control module and reset the 2 electrical harnesses to the FCM. after I reset the lower electrical harness. the engine started and ran normally.
We sat for 2 more days then started the truck everything ran normally.
but we decided to head back to civilization.
I don't think my reseting the electrical connections on the FCM was the root of the problem.
My question for anyone is could it be fuel filters, or the crank position sensor, (due to vibration The road we were on was very rough gravel). or any other sugetions.
Also the mechanic who changed my oil just prior to our trip left the oil filler cap off. I found this out when I lifted the hood, the oil level was still ok.
You can check the no start diagnosis thread in the 6.0 tech folder at the beginning of the forum, but IMHO you have classic symptoms of an STC fitting failure. Starts cold but won't start hot because of thin oil and loss of high pressure oil pressure due to the fitting leak. It's a fairly common problem on these trucks and there is an updated fitting for it. There are also a couple of threads on this problem currently going you might want to check out. Just search STC fitting.
FWIW--crank position sensor and cam position sensor on these motors rarely fails (unlike the 7.3) You can check to make sure you're getting adequate fuel by pulling the secondary fuel filter cap under the hood, but I don't think it's a fuel problem.