[Ol' Kaw Liga]

I'm new to diesels but i've been doing a lot of research on here and other places and while i've found threads with similar problems...none are the same as mine. It's an 05 6.0 crew cab with about 135,000 miles. It had 133,000 when i bought it. The guy i bought it from said the only trouble he had out of it was he had to replace an camshaft position sensor and the egr valve got stopped up and he took it to a diesel shop and they fixed the problem. It doesn't smoke a bit not on cold starts or anything and it runs good it seems. I do think it should have a little more power when you hit the pedal though just from driving my buddies trucks but i may just be paranoid. Ever since I bought it if you let the truck sit more than 10 or 12 hours it would be hard to start. It may take 7 or 8 secs to start up or i would turn the key off then back on and it would start back up. Two days ago i ran her kinda low of fuel the guage said i had bout 40 to empty which i didn't think was terribly low. Well after sitting for about 10 hours the next day i go out to crank her and it turns over fine and the batteries had plenty of juice but i couldn't get her to crank for the life of me. This was about noon and it was probably 98 degrees outside. Later that evening after work I came home with some diesel and filled her up and she started right up....this was about 7 o'clock and the temp had cooled down considerably. It started up the next morning after about a 8 hour sit and ran good the rest of the day. Today i go out to crank her at about 2pm and i can get her to crank for nothing. It will turn over but will not fire up. I know i'm not out of diesel cause i filled her up the day before and also added a can of sea foam incase i picked up some trash. I was off work today so i started doin some troubleshooting. My first thought was I picked up some trash in the line from where i ran her low. I pulled the cap on the secondary fuel filter under the hood n turned the key n she started shootin diesel out pretty steady so i know the pump is workin and its gettin fuel. I put a charger on the battery thinking it may not have enough juice to turn the starter fast enough but both batteries were at 12.4 volts and i tried starting her with the charger on in start mode with no luck still. So I came inside and got on the net and came to the conclusion that its probably some kind of sensor "hopefully" or more than likely a hpop leak or problem or an injector problem. I looked all over the engine looking for any leaks around the lines or anything with no luck. So i decided to order a camshaft pos sensor and a glowplug relay hoping it might be one of these. Well later this evening after it cooled down right before dark i went and tried her and she fired right up. What the hell??? I drove her till she warmed up then got on her and stopped and got on her again just trying to find something wrong but she was just purring like a kitten. I killed her and started her up like 10 more times with no problem. I was thinking since it's been so hot lately maybe on a cold start the oil is so hott and thin my hpop cant get up to the psi to start but later in the evening when she cools off and the oil thickens up maybe it can reach the correct psi. But if that was the case would i not have trouble restarting her after shes been running and the oil is very hot? I have run out of ideas annd by no means am i a diesel mechanic. This is my first diesel and this is just the diagnosis i can derive from interenet research. Anyone got any ideas...i don't wanna end up stranded somewhere...i'm scared to drive this thing out of town now. Would it being hot outside have anything to do with it not cranking because it sure seems that way?