Well, my issue all came down to a bad MAF (Have a new one on now - only a cheapie but will get a better one in the next month or two) I have also replaced the intercooler hoses (well 3 of them £30 from fleabay) fuel pump and filter (also have done the R5 thermostat mod - wow) and changed to Esso...

Hi Nodge68, Have you checked and replaced the breather filter - previous owner had done this. cleaned the PCV - I thought once swapped for BMW version this sorted this?

After a few days of no white smoke - it's back... Revving at 2k in neutral - no smoke when moving under load, however, when going downhill in 3rd or 4th with foot off accelerator then it'll smoke. Will have to try turbo boost solenoid next...

Blanking the EGR helped stop some of the smoke coming out of mine when I did it - as did the BMW vortex mod. Sounds to me like fuel filter/pump as I had. Either that or injectors..?

The fuel pump has been done and now when I rev to 2000rpm no stuttering and no smoke. Only had a quick run so far but is certainly driving smoother. I'll take her for a run over the weekend and report back, but it's looking good at the moment. Given these symptoms, the fuel pump & filter...

I have this exact problem too. Garage owning old friend of mine thinks that the fuel filter had not not been changed for too long putting strain on the low pressure pump which then starts to fail. The smoke, he thinks, is due to the pump not supplying fuel at the correct pressure at idling to...