Just got mine back from the dealer today for the smoke! It was a sensor FP # 4C3Z-9F452-A that had become covered in carbon, has to do with the emission control sounds as if it will be a on going problem that has to be addressed every few thousand miles on the 6Lunless you put a $32 full additive in at every fill up! Not to mention the 3 recalls 05s34, 05s15 and 59b01, no head gasket. -mad