A very common problem with motors with particulate filters in the exhaust,all geared to reducing emissions,a lot of town driving/short journeys doesn`t help and in my opinion unless they are getting a good run frequently are not fit for purpose,these filters can cost a fortune if they can`t be regenerated,my advice is if at all possible give the motor a long run in low gears at high revs to get the exhaust really hot and see if that can burn off carbon deposits in the system,if not it will need to go onto a relevant computer to try regenerating it manually,also there may be a tank of eolys/cerine which may need filling to help in the process.
cdc
August 2013
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