Sometimes truck won't start
 

I have a 2007 5.9 cummins that starts and runs but lately when you shut it off it sometimes won't start back up. It will just turn over until u use starting fluid. If you let it sit for a hour or more it will crank up without using starting fluid. Sometimes it won't do it for a few days and sometimes it will do it after you drive it the first time.

most likely injectors or PRV. i wouldnt use starting fluid if your grid heater is still in place. what is the cranking rail pressure?