01 hard start, cranks longer than normal.

My 01 has been cranking longer than normal before it starts, it even died once...but it restarted fine and stayed running. It mainly does it after it sits over night or when i get off work, which its been sitting for over 8 hours.

It has around 160,000 on it, batteries and alternator are good, temps have been in the high 60's low 70's in the mornings and highs in the mid to high 80's. Engine oil and HPOP oil are full and the oil only has about 2,000 miles on it (Rotella T6).

Is this a sign of the HPOP going out or injector issues, or...?

Thanks