My Husband once started putting petrol in his car instead of diesel, he put £5 worth in then realised, swapped to the correct pump filled the tank..lol.the car has never run as good!! He wasn't bothered as it is a company car, it has done 100,000 mike since without any problems.
it all ran perfectly once my "mistake" was drained out billy.. at a rough guess its had over 700 miles of arduous towing mileage under it belts without a murmur from it since my "mistake".. it was actually the third fill up since leaving home the day before..
it wasnt neat petrol it had in more a 50/50 mix.. half a tank of diesel already in there with me adding half a tank of petrol.. if the tank had have been more empty and filled with neat petrol i dont think i would have got far without some serious bangings and knockings.. he he
a pic from the other side of the rock.. the only company we had up there were snowploughs and gritters..:)