How do you fixes your Toyota Camry 2.2 4-cylinder from black smoke and burning gas in your muffler?

How do you fixes your Toyota Camry 2.2 4-cylinder from black smoke and burning gas in your muffler?
Black smoke means that you have oil in fuel, which implies that you have internal oil leak. You basically have two choices. First one is to use special additives to seal the leak (it might be too late). Second is to replace leaking gaskets, it's most likely valve gaskets.