Diesels need air, fuel, and compression to run. You said you had filter problems. have you confirmed fuel in system and not air locked? Did you bleed...
Sorry your having so much trouble with your 6.2. I'm no whiz at the 6.2 but if it all started when you changed your fuel filter, I would start there....
Thought I'd move the PS pump conversation back over to the 6.5 forum.
Weather was pretty good, this afternoon (for a while), so, I fired up the Burb...