Once upon a time when I was much younger I found myself far from home and low on petrol and low on funds so I..... ah...'borrowed' a quantity of diesel and poured it into the petrol tank of the elderly Austin I was driving at the time. To my amazement once the Austin got into its stride it seemed to be running with much more oomph that I was accustomed to. The engine was rather well worn and tired and was due to be replaced with a newly overhauled engine so I wasn't too worried about what the change in fuel might do to it.