I have run a 300 tdi county from new 1997 - I still have it - 28 mpg towing or not . . I have just bought a SWB 2.4 TDCI , have fitted new ECU , mileage when towing down to 15 mpg ! yes!. Is this normal , selling it , could by a Merc AMG and get comfort and better mileage , Has any one else...