Good luck. Mine fluctuates between 12.2 and 12.8. I just ran out to the store and the truck obviously went into a regeneration cycle and it dropped to 12.2, but on the way home, it started to come back up and was at 12.5 when I pulled into the garage. I have also found that I get better mileage out of certain brands of diesel. The best mileage I have gotten so far was with a tank full of Chevron diesel. I also run 16 ounces of Diesel Kleen in every other tank. I bought the 96 ounce bottle from Walmart and a 16 ounce bottle from Advance Auto Parts. I just refill the 16 ounce bottle from the 96 ounce bottle and keep it in my center console so that I have it when I fill up.