Hard start, smoke, rattle, no power, mpg drop - no codes

So a few days ago a neighbor replaced my valve and rocker gaskets to stop an oil leak. While he was in there, I had him put in new wire harnesses to the injectors. The next day and I'm smokin all the time and the normal diesel "rattle" is a higher pitch than what I'm used to. A small increase in the pedal and I'm blocking out the highway with black smoke. If I get on it to pass a semi or something large, my engine will not throttle back until at least a 1/4 mile after I let off. The harder I hit the pedal, the longer it takes to throttle down.

Reading all the posts on here, I figure I've possibly got an air problem. Now I didn't read all posts but the last part about my truck not throttling down is something I didn't find which is why I'm creating yet another post.

I've seen all the posts about checking the intercooler boots and possible injector issues but it seems to me a mighty odd coincidence that this happened right after changing out a couple of gaskets and wire harnesses. Is it possible that a wire harness is defective?