Well the other day, My egr cooler failed, along with 2 injectors.

Replaced them.

Ran great for a day, parked it at work, would crank crank and crank. finally started was still running like air was in the system...finally cleared up.

Parked it the next morning it wouldnt start at all. batteries just died trying.

Checked ipr, icp and all good.

could it be my HPOP?

2006 6.0 201,000 miles.

 

Could be a number of things. Are you sure you got all the air out of the fuel system after the injector replacement? What's your fuel pressure at? I'd start there...