Originally Posted by GMScott

Well guys, here's my experience with using fuel additives in 3 Cummins RAMS, a 1999 (bought used with 45k) 2004.5 (purchased new) & current 07.5 (purchased new) With the first two I used additives religiously, meaning almost every fillup and with great benefit, ie. improved mileage & performance. It was very handy when I had picked up some lousy fuel on the road, indicated very quickly by the overhead. I only use the overhead for baseline readings, I have a digital fuel monitor that came with my aux. fuel tank for capturing actual fuel use. I started the same process with my 07.5, not getting any real improvements and within 35k miles, mostly highway @ 75 m.p.h. I was getting EGR codes, poor performance and lousy fuel mileage. This was before all the flashes & EGR problems started showing up. They cleaned the EGR which was full of soot & a gummy substance which required a "special" Chrysler cleaning soap. I continued using additives and the EGR clogged up two more times within less than 20k miles. I was advised by DC to NOT use any additives. I agreed to not use them and have not had an EGR code since. Truck is up to date with the flashes except for the last one - AX I believe. I used the Power Service additives mostly and sometimes the Howes as they were the most available. My reason for using additives with the 07.5 was the lubricity/cetane levels of ULSD bought on the road. So far so good without additives with 110k miles on the clock. What turned my mind concerning additives was a very exhaustive & specific lab report testing all the major fuel additives. The report is floating around on these sites - I don't have a link to it. Power Service & Howes were in the bottom 3rd as far as effectiveness AND both were putting in foreign materials that could possibly cause harm in the long run, either to fuel components or the NOX filter/DPF filter. That sealed it for me, as you can see I pile the mileage up on these trucks pretty fast and I don't need to be wasting time in the shop or paying for expensive repairs due to additives. I don't say snake oil since I have enjoyed the benefits of fuel additives in my two previous trucks. But for me, additives in the 07.5 is a NO NO.