My regularly serviced 2005 1600cc Ford Focus automatic has never given a high mileage per gallon - usually about 28-31mpg for short and medium journeys although better on a long journey. Lately this has become 18mpg for shortish journeys. My 2000cc Cavalier auto never gave such low mileages. Can anything be done to make things better? A mechanic friend thinks that there are no adjustments that can be made on modern engines with petrol injection but surely there must be a cause for this high consumption. Any helpful advice you can give will be very welcome.