that was one of 2 x 10 6 hits for "economy driving"
It's the car or the driver. Throw out excess weight, ensure the car is in good condition tyres at correct pressure ( higher pressure better economy) filters clean no fuel leaks then learn economy driving. Get the ECU checked to ensure it's working and getting the info it needs from sensors. Exhauist in good shape (not blocked cat) I can easily put 40 miles into an hour in my 1.8 weekend, while getting better than 35 miles to a gallon.