When I first got it, I was getting great 18-20 MPG. Then all of a sudden last year it's been averaging 12-13 MPG without the Front Runner Slimline II roof rack. 3 months ago with the roof rack, I somehow was averaging 13-14 MPG. Just recently I got 200 miles off of a full tank (18.5 gallons) or 10.8 MPG. My calculations are based on always clearing the number of miles driven on odometer A, filling up until full, and divide the number of miles driven by the number of gallons put back into it. Example, 250 miles (driven on A) divided by 18.523 gallons (filled back up) = 13.497 MPG. My driving habits are roughly 70-75 MPH and the foot pedal never goes past half way down to the floor. I seriously feather the pedal to hold speed or put it in cruise control. So, please save the don't drive fast comments. There are absolutely not warning/check engine lights, error codes, leaks, smells, or anything. Looking at the D4 Workshop Manual PDF on page 2584 under Excessive fuel consumption it has the following possible causes: Low-pressure fuel system fault Fuel volume control valve blocked/contaminated Fuel pressure control valve blocked/contaminated Fuel temperature sensor leak High pressure fuel leak Injector(s) fault Exhaust gas recirculation (EGR) valve(s) fault I'm pretty sure if any of these are possible causes it would have tripped an error, so instead of checking everything I'm asking for some advice on what I should start at. I also brought it to the dealer and they told me that it'll be, forgot the exact amount, $300 for them to check it out and since it was well within specs (12-13 MPG) there's really not much they can do. Can someone point me in the right direction for things that I can do myself? Thanks!