Does anyone else have a dieseling or spark knock type noise under acceleration? It sounds like a bad case of spark knock or like the old 7.3's. I believe it may be a shifting issue like the trans is shifting to fast and lugging the motor. I do not know anyone else with one of the new trucks so it is hard to compare. Beyond the obvious, it is hard to know what these new motors should sound like. I can get in any of the old diesels and tell if there is an issue. The new ones have not been around long enough and therefor a good diagnostic (tuned ear) is hard to come by.