Okay, so it's been a while since I've been on the forums. Now that I have some more free time I'm gonna be a little more active.

Since my last post, I've done efuel, 180/0 FFD injectors and diesel tech of Chattanooga rebuild my PCM and 1023 tuned my hydra. While this setup solved quite a few of my problems, the truck is almost perfect except for two very annoying and mildly concerning issues:

1. When coasting down a steep hill for an extended period of time, the truck sputters at about 2000rpm and spews a massive slurry of black/white smoke when I reapply the throttle (also, yes I know throttle isn't the proper term for a diesel but i dont care). Best analogy I have is that it's congested and it's clearing its throat. That's literally how it feels. the truck bucks and sputters and then it clears up and goes RIGHT back on its way like nothing ever happened. Makes for concerning drives, especially when the mountain pass this ALWAYS happens on is often times very snowy and it blinds everyone behind me.
Could this possibly be a sign of a bad turbo, or perhaps maybe an issue with my valvetrain? My initial guess is that the turbo is bad and that it's accumulating oil in the turbine housing when coasting and when applying throttle it has to push all of that through either the engine or the exhaust. Thoughts?

2. The truck has a dead miss when VERY cold started--it clears up in a bit. This is probably cuz the engine is clapped. But, on regular cold starts, it starts like a dream now with the new fueling setup; doesn't lack power or anything. I only now get issues when it's hot--i.e. driven on the highway (2000-2500rpm for any drive greater than 25 minutes, really). What happens is it sounds like it's misfiring. The truck still feels smooth, and I don't notice anything odd--if I was deaf, I wouldn't be able to tell any difference while driving. It's most prominent at partial throttle, where it literally sounds like it's just pushing air on one cylinder. Same with full throttle, as it makes boost. Sounds like a horrible exhaust leak, which I know I have, but that doesn't explain why, after I come to a stop after a long trip, it idles rough and shakes the truck when idling after these long drives. When I ran a contribution test, the test passed fine, despite the fact I could hear certain parts of the test sound significantly worse than the others. Also, to boot, it is not UVCH--I just did a super duty UVCH conversion and the .50 mod and it is connecetd all the time, at least according to my contribution test and buzz test.
My thoughts are two things: the fact that the engine has 335k hard, unmaintained miles and it's probably just got dogass compression. Either that, or my HPOP is failing (perhaps relating to the first concern?) and it's starving injector 8.

I have a 17* HPOP and a super duty waiting to go in, just need to fix the BMW and pay for next semester first

TL;DR: Truck has a sinus infection and gets drainage out the turbo(?) when coasting down steep grades for extended periods of time, when driving on the highway for extended periods of time it feels like it develops a misfire, idles rough at stoplights during the trip.

Cheers!