Need some suggestions, what causes black exhaust smoke?

 

Just got info and hoping this applies also
What Does the Smoke from My Exhaust Mean? » AutoGuide.com News

 

Black smoke usually indicates a rich fuel mixture. You'll probably have soot on the inside of the tailpipe too.
Not sure how to remedy that on the D2. I'm assuming a sensor would be misbehaving somewhere.

 

Yes, rich mixture will cause black smoke. Perhaps one of your O2 sensors is stuck lean and driving up the fuel trims? Keep in mind, the extra fuel is NOT good for your catalytic converters!

 

Could be something as simple as clogged air filter, or obstruction in intake somewhere. The tube going from the air cleaner box to the fender can collapse and this is where the air going into the airbag originates. Many of them are deteriorating at their age.
Just something to check.