Fantastic, thanks for the info. Apart from poor fuel economy and general inefficiency, is there any reason to do the APC urgently? If not, I’ll just ask them to do this during its next service, rather than pay to have it done separately.

I put in an EGR blanking plate to see if that was contributing to the problem, but it made no difference to the MAF readings (as I suppose you would expect). I'm going to see if I can visually inspect the hoses for leaks, but I'm not sure how much access I'll be able to get at home. It's odd...

Good evening, all. I don't mean to hijack this thread, but I have a very similar issue here with my 2008 Freelander 2 TD4. I don't have any black smoke issues, and the car is well-serviced and otherwise seems to be running quite well for its age. I noticed that fuel consumption has crept up to...