Dicovery maniac
New Member
i have a 300 tdi comercial discovery which has had a few things done to it which would put mpg down a bit but not by this much should average at least 27mpg and i am getting around 20mpg is there a common fault somewhere been like this for a while, also had new head gasket. cylinder head (new not skimmed) and rocker shaft but was doing terrible mpg before this aswell can anyone help