Originally, it was estimated that the combined city/hwy fuel economy for the Titan XD was at 22.7mpg but reports from various publications suggests that the Motor Trend has recently published the real world fuel economy numbers of a production model powered by a 310hp Cummins 5.0-liter V8 turbo diesel engine and according to forum member Tiger7, a third party called IntelliChoice was employed to run the test. The Titan XD fuel economy results will give buyers an idea of what to expect when driving around a truck with a gross vehicle weight of 8,500 pounds.City: 15.8 mpg (14.9 l/100 km)Highway: 20.8 mpg (11.3 l/100 km)Combined: 7.7 mpg (13.3 l/100 km)It was not mentioned in any of the publications if this was with aor if the Titan XD was towing something near itsIs the Titan XD’s preliminary fuel economy above or below your expectations? Speaking of expectations, what are you guys expecting the fuel economy will be once the XD is saddled with more weight?