Oil cooler may be ok what is the ECT once up to operating temps down a close to level highway? You should be seeing 194 +or- a few degrees that is of coarse unloaded.
The majic number is 15 degrees above the coolant temps on level ground at 65 mph empty, that is when you need a new one.
Odds are very very good the hard starting issue you are having is your FICM. Whenever I see hard starting followed by I have a new alternator and batteries it's a no brainer.lol
The first thing that gets destroyed from low voltage is the FICM, it has a DC/DC converter for the power supply it takes 12 volts and runs it up to 48 volts for the injectors. When it drops below 12 volts the power supply board makes too much heat and it desolders itself usually at the 4 (Dale .0075 resistors).
The connections get bad enough where it cant make the power anymore, if you are handy with electronics you can repair it yourself with a good pencil type soldering iron.
If not handy lol, go with: Ficmrepair.com he will fix you up........
If you put a scangauge on the truck to check the ICP pressures as well as the IPR values to see how the hpo system is doing to rule out any hpo problem. But 36 volts will cause all kinds of starting issues.
Good Luck with it..........
Last edited by mhatlen; 03-06-2013 at 05:05 PM.