Lad next door has just bought a p reg BMW 318 td off his mum, shes only had the car a few weeks, bought off ebay with a knakered aux drive belt tensioner ( i think it was anyway

) they fixed that, drove it round for a bit, his mum decides she doesnt like it and the lad buys it.
drives it for a few days, (just general driving, says he didnt put his toe down at all) and it starts to smoke like hell out of the exhaust.
decides to sorn it for a bit to find out the problem so reverses it off the layby at the front of our house onto their front garden, runs it for 2-3 mins, and then turns it off, takes keys out and stands next to it talking to his sister.
NOW....
the car then decides to start up again, ON ITS OWN!! and seems to dump its entire contents of oil into the ehaust!! causing a home made flamer kit and HUGE clouds of smoke which filled the entire road and all the surrounding houses.
He craps himself and tries to stall it, then, realising the flames, decides to get it away from the house so floors it over the garden, accross the pavment, accross the grass, down the kerb and the layby and stops in the middle of the road, skimming the other neighbors car because the steering lock it still on!! the car then cuts out and sit there still smouldering and the lad is nearly in tears!!
i cant understand what would cause this though......
PS: this is a TRUE story belive it or not!!!