HELP.. exhaust smells bad

Ok.. car is running super rich.. my Air/Fuel guage is solid rich.

i swapped the cat with a new one and swapped the header o2 sensor. also swapped the distributor cap and rotor.

today im changing the fuel filter, spark plugs and wires.

i dont know what else it can be and need help.

when i removed the old sensor and cat.. it was jet black! and its only going to be a matter of time before it happens again so i gotta get to the source


any ideas