I have a 2018 titan xd deisel. I had to have the feul system replaced from front to back. Since they fixed it I have lost 60 miles to a tank. Before I pours DEF in my tank and started it. I was getting 100 miles before it would even come off of full. Now I get 49 miles. I Also don't think my truck is regining like it's suppose to. 2 weeks ago I had to have my KNOX sensor replaced. The dealership did a force regin and said it shot so much black smoke and other stuff out they had to move the car beside it to keep it from getting ruined. My question is what kind of gas mileage are others getting. I get 21 in highway and I get 17 in town. I get 13 to 10 towing my 3000 lb boat. Also how do I know it is in regin mode. I have Nothing on my dash that shows any thing like that.