2007 Mazda 6 diesel, 98k miles. One year ago, car would slow down approaching even slight gradienst needing many downward gear changes. This followed by all the DPF problems finally needing new filter , sensors etc. new filter (patterned version) clogged twice, patterned sensors failed resulting in severe loss of power on motorway. Finally had filter 'gutted' and ECU remapped. All ok for few weeks, now getting random loss of power/ slow throttle response. On last two occasions, driving down a steep hill seemed to rectify that ???