I have had several diesel pickups, (2001.5 Cummins 5.9, 2003 Cummins 5.9 HO, 2006 Powerstroke 6.0, 2015 Powerstroke 6.7, 2016 Duramax) and never added any diesel fuel additives at all, ever. No engines problems at all from any of these engines from any of the various manufacturers. Matter of...