OK, I know you have done most of what I am going to ask about, however, please bare with me as I am asking to help my brain troubleshoot.
Can you please tell me the following :
1) amount of fuel in tanks I should have at least a 1/4 tank in my front tank, i don't use the rear. Cant know for sure because the gauge doesn't work. ~150 miles on full tank
2) color of air filter (dirt wise) Fairly clean, probably could stand to be replaced.
3) do you see ANY leaks, damage, ANYTHING of fuel lines/system from tank to IP Haven't looked much underneath, But it does pump the fuel pretty steadily, and considering it started up easily and ran before the IP change, i assume its alright
4)do you have dual tanks. If yes, and if electrical, Does the selector switch activate the fuel selector valve steadily and solidly Only use front tank, rear one is leaky
5)last time all fuel filters changed Main screw on fuel filter was replaced MAYBE 500 miles ago
6) we know the injectors are new BB codes, so skip that part
7)can you find ANY restriction of air flow going into engine Tried with and without air cleaner setup
8)age of lift pump Just replaced, airtex
9) does your fuel tank(s) have a fuel sock in them. In vehicles with a fuel sock, sometimes the sock can be sucked up into the fuel tubes inside tank and cause restriction Dont know about that one
10)how strong does engine crank Cranking good, batteries just charged form other truck. slows a bit when GP's kick on
11)where do you purchase your diesel "safeway" its a fairly new and clean station if that matters
12)has the problem ONLY happened since colder weather has started
Will not start ever since i replaced the IP. But it did run at first, and it did run good until i shut it off.
Sorry for all the questions. I need a basis of understanding to knock my head around until I figure out how to get you fixed.