Ever since we bought our Fiesta 1.4tdi 3 years ago we have been averaging MPG consistently in the mid-fifties. It has now suddenly dropped to the mid forties, and we don't exactly drive the car hard. I did have a problem with a small split in the fuel pipe a while ago but this has been repaired and the MPG was re-set at the time using the button on the indicator stalk so I know it hasn't taken the fuel leak into account (hope that makes sense!), i.e. MPG has been under 50 since the car was repaired My mechanic has cleared any error codes that were present following the leak but economy has continued to drop. Any ideas as to an explanation for a sudden decrease in MPG and possible remedies? I suspect it might actually be a problem with the computer giving a false reading - I was briefly stationary in the car last night with the engine running and the computer showed the MPG continuing to drop and that never previously happened. Thanks in advance for any assistance.