Fluctuating Idle when Hot, about 30 rpm,
Fuel pressure at 10 psi,

After several hours of driving , when I stop there is a slight
fluctuating at idle (~30 RPM ). after abot 20 minutes shut
down, restart, Idle is back to normal,

All other driving is fine, and no codes in window.....
Problems ahead, or don't worry about it,

( Only 3800 cummins miles,) love the truck.....

 

u are worried about a 30 rpm fluctuation ? u must have some very precise tach. dont sweat it.

 

The A/C compressor cycling on & off? Try shutting the A/C off when it is doing it.

I would not worry about it.

 

My 99 does that when Summer comes every year. Seems as though when you come to a light and press in the clutch the engine drops below idle speed then jumps above and back down in an effort to find idle rpm.

The A/C being on even makes it worse. Its been doing that for 4 years. BTW, its the original VP 44 going on 210K. I wouldn't worry if I were you

..................Jim