I just got the same problem. Luckily my smoke detector woke me up. I thought I had an elctrical fire somewhere in the walls, but it turned out to be from the furnace. The unit is (only) nine years old. A technician told me the motor and transformer were fine and it must be a crack in the combustion chamber. I am without heat until a repair company can come out monday (it will be 5 above tonite where I am). How can an oil furnace make this electrical odor?