I bought my 2006 Mazda 6 2.0 diesel SAKATA in November 2007. For the first 3 months the car was fine no problems. Thereafter, I’ve had the same problems described on the site by other Mazda owners, especially with the DPF and oil levels rising to quickly. My 1st bad experience was after 3 months on the M74 motorway, my wife and grandchild on board doing about 65mph. All of a sudden the engine revved uncontrollably hitting 5,000 on the rev counter then I noticed a lot of smoke coming from the rear of the car I took my foot off the accelerator but this had no effect on the revving. I managed to get the car onto the hard shoulder but could not get the engine to stop. I eventually managed to switch the engine off. After a few minutes I started the vehicle up but once again the engine revved uncontrollably again I managed to get the engine turned off, we sat in the vehicle for about 10 mins then started the engine which seemed ok. I drove off only to notice the DPF light was on then later the DPF light started to flash and the engine management light came on, I got the car home and called the dealership who told me to contact Mazda recovery who uplifted the car and took it to the dealer. Dealer told me it only needed an oil and filter change. I explained to the dealer and Mazda Service centre that I thought the car was dangerous and explained what had happened on the motorway: the engine suddenly revving uncontrollably. All they said was that it was probably due to the high oil levels and oil filter. They would have the car checked. Car was checked, nothing found. Changed oil filter and oil and reset the computer. I have had the car in many times since, all relating to the DPF, SMOKE and HIGH OIL LEVELS. They keep giving me one excuse after another. They say it needs oil change, filter, catalytic converter, thermostats faulty, the list goes on and on. They also said it could be due to not driving the car properly as the car was made for motorway miles and not short journeys. In fact I do 500 motorway miles a week. The car had 26k miles when I got it. Now has 56k miles. No one will give me an explanation to what the problem is or do they really know? Mazda admits the car has been badly designed.