Hi all just wondering if you couild help with this at all, the above car engine light came on and i was told it needed a cat regen, went and got this done at the mazda dealers, after getting new injectors (wallets still hurting) they told me it was too blocked up and would need a new Cat Converter, however they did offer to try a new solution which has come onto the market apparently which is 95% effective (didnt ask what it was called) in these situations and if it worked it would avoid me shelling out a shed load on a new cat converter / dpf filter, suffice to say it appears to have worked and the car is working fine, but the exhaust is making a fuunny sound in the 30-40 speed range (3rd gear) the best way to describing it would be a loud Brrr noise kinda similar to how my old 306 diesel sounded when the back box fell off once doing a quick visual the exhaust seems to be fine, i will ring them tomorrow to find out if its normal, but has anybody had any experience of cat / dpf regens, will the exhaust sound go back to normal in a few days or am i worrying for nothing, its my 1st car with a DPF and i have only had it about 3 weeks so i cant compare it to how it should have sounded. any and all suggestions much appreciated and thank you to all contributors in advance. By the way the dealers said that as this is the first car that they have used this solution on the company that provides it did it as a freebie or trial if you like so cant help with any pricing on this if any body else has a similar issue (the dealers impressed enough to give it a go)