My 2007 Subaru Outback has 85,000 miles and I am trying to sell it. The local Subaru dealer and a mechanic both say that the head gasket is leaking some oil and needs to be investigated further for a complete diagnosis and repair. (It was not leaking into the cooling system at that time). The car was running fine and then a buyer took it to the mechanic to get it checked out. The buyer didn't buy it and after the car sat for a week it started this behavior of dying after starting. The lights go on and the radio will play and the battery seems fine. There is plenty of gas. There is a lot of oil on the right side of the car. Could this be ignition coil, mass airflow sensor, or what? Please help!