I have a sprinter 318 (v6 automatic) and have noticed that I am suffering about a 20% loss in MPG (its actually in kilometers). The van has 65K (KM) on the clock, has been over serviced, has ever only used MB parts, suffers NO air leaks, and yet I am loosing about 20%. A couple of friends (Mechanics) have suggested it "might" be the air flow meter. Rather than spend nearly €300 on the off chance that it is the meter, does anybody have any suggestions what else might be the problem ?

Thank you, new to this forum