Millers Diesel Power Ecomax...

[BongoBongo123]

good stuff, less than £10.00 a bottle on ebay. Does 10 x 50L tanks of Diesel. Running a tank without it at the moment and fairly sure it pulls better and seems all round smoother with, like a newer engine. I think it does indeed help MPG, though I have not done exactly scientific measurements but I think it helps. if you are planning a long run try it out it certainly won't break the bank.

It takes the cetane level up which I think might be like petrols octane which would account for better fuel economy/power. Also cleans injectors.