My 1.9 tdu fuel consumption seems to have deteriorated over the past few weeks, down from around 50 mpg to around 43 on a run. It is not due a service yet, and I have checked the tyre pressures. Does anyone have any ideas please?

thanks

Time of the year, warmer weather, A/C on.

 

Did you have the car last year in the Summer?

Brim to brim calculation or mpg readout on the dash?

Air filter? 

Carrying more weight in the car?

Binding brake?