Okay so I've been running premium diesel and I've used to bottles of forte I've done 54 miles I've rev'd my engine till to 5000 rpm and there's black fumes coming out. Before I used the cleaner I did Rev the engine and it was just white so I can only assume that the cleaner is working and the black stuff coming out is the rubbish that's been stuck on my turbo vanes ?? Anyway will keep posting to see if it works