air intrusion or IP going out?

[miles1400]

truck cold starts in the morning fine but when i start it up after work it runs good then starts stumbling, then evens out again. there was no drips or wet spots under the hood or under the truck. the truck has 199k on it, i believe the injectors are original and the IP is a reman with 124k on it and i know they have a life span of about 125k. fuel system is air tight as far as i know, the truck does not smoke/haze either when warm which i know is a sign of a failing IP. i have not changed anything with the fuel system since the fall when i did the fuel heater plug, a CDD soft feed line and a new fuel filter.

i dont know if this is helpful but the ip is turned up 2 flats and the max egts i can get is 800F going up a hill on the highway doing 65-70

what do you guys think it is?

 

[Farmer Rock]

that sounds more like air intrusion. Be sure to thoroughly check the hard lines before the lift pump. My truck kept getting pinholes on the top of those lines, so it didn't leak but sucked a lot of air and was surging. Considering we live in basically the same climate, it's possible your lines rusted out the same way maybe.



Rock

 

[MtnHaul]

I'm sure you have a bit of air intrusion/fuel drain-back.

Now as to the low EGT despite 2-flats turned up I had the same/similar experience. I turned my pump up about 1.5 flats but EGTs were below danger levels. Eventually I figured out that the accelerator cable was broken. 15 minutes and a few bucks later with a new NAPA cable and it was a whole new truck. Of course your pyrometer could be broken. . .