I have a 98 passat tdi i recently changed the air mass meter which has made an incredible difference to the power of the car only problem being is that now when i excelerate quite alot of grey smoke comes from the exaust, i have been told to use redex to clean the injectors, can anyone tell me if this does anygood or not. thanks.

yea its not bad just get regular cleaner for the injectors...u no what even works better is brake cleaner

Grey smoke is more likely the turbo leaking oil.

Or grey/black smoke is also caused by very rich mixture. VW sells injector cleaner in the parts department, i believe its called sure shot diesel fuel system cleaner. Pretty much seafoam for tdi.