Engine was recently rebuilt by supposedly a good mechanic. I'm looking to purchase this car. BUT, it smokes, all the time. Not a ton, but also enough to be worried about. What could one suspect it is? Rings, valve guides, way too rich, MFI problem, some sensor problem? Engine runs fairly well and it is, BTW the original 2.4S MFI engine that came with the car. SO, what are your bets on? TIA