I claim no specific knowledge about your situation but would like to ask a few questions. You mentioned "delete" so I assume you removed the DPF. What did you do with the sensors, specifically the pressure differential sensor that is on the DPF? Do your "tunes" specifically address these sensors as part of the install? Can you correlate the message specifically with the removal of the DPF or did you do all the work at the same time (DPF removal, software, EGR)? My thought is that lacking the proper signal from one or all the sensors the truck thinks the DPF is clogged or has a hole in it. If you aren't getting some sort of "Drive to Clean" message, I am thinking the latter is more likely. Just a thought....