Diesels are a different breed. At least with the Ford diesels, they like to be worked. A diesel that is used as a grocery getter is more likely to have emissions issues. I carefully monitor my regens to make sure the Diesel Particulate Filter is getting clean. I haven't kept up with what additives the Titan guys with diesels are using. I'm using Better Diesel Fuel Burn Catalyst. It seems to do a good job of keeping my DPF clean, with shorter regen cycles.