Has anyone else seen a drop in fuel mileage in their diesel trucks in the last 5-6 months? Reason being my 06 Dodge I checked around thanksgiving got 19.7 on a thousand mile trip, usually around town 17-18. Last 3 times I’ve checked it’s now 14.6 and consecutive checks this summer. 134,000 miles on truck and still runs great. Not using that lie gauge either, actual gallons into odometer miles. In 15 years it’s never got that bad of millage. Do you think the cetane rating has dropped