Hello
I drive a 2010 Mazda 6 Estate 2.2 ts2 diesel manual. Its high mileage at 71k, but has been running tip top with an average MGP of over 46mpg, with with both daily town and motorway running. In the last couple of weeks, I have noticed that it sometimes sounds very rough and on the motorway at steady 70mph, I am getting instant 20mpg instead of around 50-60mpg when it was running fine. After a while it seems to go back to good running and expected MPG. There is no obvious mis firing. I had wondered if this was some passive DPF regen thing, but I have no DPF lights on or flashing at all and would have expected this if it was a DPF issue. Before I book it in, has anyone else experienced this? Is it worth putting in some additives to clear it out or that expensive diesel stuff-or will this knacker the DPF as the manual suggests it would.
Look forward to any knowing replies....
P