[ope126]

Have you every tried using a Diesel Additive whenever you fill up?
Or try a DPF Additive every now and then.

I always use BP Ultimate Diesel from the same bowser and keep the receipt.
I have also been adding CleenDiesel for the past few years with every tank. I now use Morey's Diesel Smoke Killer as CleenDiesel is no longer sold retail, only commercial.

There are a variety of additives on the market, do your own research and use what works for you. I would say it is better to use, than not to use!