What is the problem?

[tgolden068]

Any insight would help, please.

I have a 03 6.0 Ex, as the weather got colder (<40 degrees) the truck would not start. I plugged the block heater in 4 hours or more and after a few tries (could hear the flywheel engage and the teanny temp rose) it would finally crank over. Once the outside temp hit zero it had to be plugged in whenever it didn't run or once I shut it down it was a bear to start, even with the engine still hot. It is now back in the twentys here in south central PA and if I do not plug it in at least 4 hours it will NOT start.

Now, I have been leaving it constantly plugged in. When I crank it the first 3-4 times nothing happens with the motor. Just the starter/flywheel crank. Then the next few times the motor will start to crank but after about 1-2 seconds of it turning it quits. I have to cycle the ignition a few times to get it to start. Once it does start it starts fine, not rough, does not run rough. No power lag, no pressure drops.

The only consistancy is that it is plugged in and will eventually start vs if it isn't it will not start. I am at a loss . I have a job where I can plug it in while I am at work, so it isn't the end of the world for me to keep doing that, but if it is something that I can fix I will like to do that.

No codes, no power loss, both batts are 12.5 or so while cranking.

I appreciate any insight you guys may have.

[tgolden068]

Anyone... Bueller...