I'm a new Touareg owner -- 2012 TDI Executive with 77K miles. I just finished a 200 mile round trip towing a load, which is my Can Am Maverick Trail 1000 side by side on a single axle 14 ft aluminum trailer. I'm estimating the total weight to be 2800 lb with about 300 lb tongue weight. The trip is maybe 40% flat and the rest hills and a total of 30 stop signs/lights. Speeds ranged from 30 to 70 mph. According to the vehicle computer, I averaged about 15 mpg. On the freeway flat straights, the real time computer showed 14.5 mpg at 65 mph. I've read many posts from other TDI owners claiming close to 20 mpg on the highway towing more than 5000 lbs. Something is amiss here. Prior to the trip I ran the "original unknown type and age" fuel down and put in 22 gallons of Marathon diesel with 16 ounces of Power Service Diesel Kleen with Cetane Boost per my local VW service manager's suggestion, and I was "getting on it" sometimes going through the gears manually to get over 3000 rpm while upshifting. Something I did notice is that in 8th gear and 65 mph, when I'm going up a hill, I can sense a very slight surging -- almost feels like a gas engine that's got an ignition issue or bad gas. That's the only time I notice this, but it can be repeated consistently. This is my first diesel vehicle so I'm a complete newbie when it comes to how they're supposed to run. Any suggestions would be appreciated.