Oldsmobile/Buick Repair: Rough running engine, black smoke out exhaust, mass airflow sensor, olds bravada

Question
I have a 1993 Olds Bravada Smarttrak.  Tune-up was done, the "accordion hose" from air intake was replaced but it still runs rough and black smoke comes out of tailpipe.  If you take off the hose from air intake it runs a lot better.  Do you or can you give me some idea as to what I may look for?  Possibly a sensor that is bad or the ignition coil?  If the hose is on, it's as if the engine is sluggish.  Thank you for any ideas you may have.

Answer
Hello Christine,
My obvious question would be have you removed and checked the air filter, and the intake ducting to see if some kind of animal built a nest in there?
Then there is the mass airflow sensor, which could be covered with dirt.
Don't think you will just clean it though. it is very fragile, and some kind of cleaner that doesn't leave a residue is needed.

Van