Hi Guys.
Black smoke fixed:
Changed clogged fuel filter £40 total from garage
Changed dirty air cleaner £5 from ebay and fitted myself.
White smoke and most of the bucking
Buy 'premium' diesel and mix with red X for diesels. £60 for a tank, £5 for the red X and use half a medium bottle for a tank.
Find the quietest bit of motorway and run the engine past 3krpm for 140 miles
Repeat for another 140 miles.
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I tried to get garage to re-code the injectors, but they'd have none of it and I didn't want to spend another £500 to buy and fit injectors on a guess and I reasoned that if the fuel pump was an issue there would be other symptoms. Pretty much lost my faith in garages at this point.
Anyway - No more white smoke or smoke cloud at night, some minor bucking if it runs below 2k rpm when it's cold, but picks up better and feels generally snappier now.
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I had a look over the topics and cheers for the help! Injectors were pointed out months ago and I had a feeling when I got it there was an issue with them. Will see how it goes.