blowing black smoke

You probably need 6 new spark plugs. I would start there then check your ground wire.

 

I'm guessing it's one of your sensors like barometric or oxygen. I think a dealer could find the problem in minutes.

 

Have you checked air to air for leaks?

 

Try unplugging the egr valve and see what happens. ISX sensor typically plug up over time and need replacement or cleaning. Sensors such as exhaust pressure, egr differential pressure and intake manifold pressure are the main ones.

 

Right hand side, just below the front of the exhaust manifold. It is the two wire connector. Do this at key off. Having it unplugged will cause a check engine light. Basically the egr valve is probably stuck open. This is leading to lower boost and excessive black smoke. Usually when the valve is stuck open the position sensor will detect this and log a code. Some times the valve opens because it is damaged internally, but the position sensor thinks it is closed. Unplugging it with the key off is the best chance of it being closed on its own.