My Mazda 3 recently had a refill of the DPF fluid and forced regeneration by a main dealer due to an engine management light coming on, which produced DPF related error codes.

The car subsequently ran fine for a couple of months, however, the engine light has come back on and again the error codes point to the DPF. I have also noticed that acceleration power is well down and fuel economy has dropped from the usual 50mpg to 40mpg.

It is currently back with the dealer, as I feel my usual local garage may be unequipped to deal with the issue, but I would like some ideas for what may be wrong and what may put it right for when the garage come back to me