Hi everyone - New on here, and hoping someone might be able to help...?

I have a Mazda 6 2.2 MZR Diesel
The car recently has developed an issue where it has simply no power below 2500 rpm in 3rd / 4th gear…
If I drop some gears and drive it hard, it pulls OK, but not great.
The car has had a new Airflow metre approx. 10 months ago and up until recently has been spot on.

The car is regularly serviced by the main dealer.
I have had the car code read and no fault codes came up at all!

I have also run a cleaner through my DPF but it is still not right…
I am wondering if I need to bite the bullet and change the DPF completely.
Or could it be something else?

Mileage of the car is 112k

Does anyone have any ideas??

 

Was the code check done by the Mazda dealership?