Black smoke

Good evening

Black smoke could be coming from injectors. If one or more is delivering more fuel than needed, it will run rich.

Have you ever had the injectors cleaned??? Shops offer injector service where they disable the fuel pump and run a solution through the fuel rail that breaks up all the carbon deposits and makes them work much better.

Roy

If you have too much fuel pressure, over 55 psi, maybe due to a kink in the fuel line, then that also could cause the black smoke and running too rich.