black smoke from the tail pipe?

[Missouri240D]

my 82 240d sometimes blows black smoke from the tail pipe, at highway speeds of 55+ and at low speeds around town. not a tremendous amount but enough to notice. can anybody tell me what might be the problem and how i can fix this. i don't like smoking on people.

[Simpler=Better]

Lay off the gas pedal, black smoke is unburnt fuel burning in the exhaust. Check your air filter, you're not getting enough air to fully burn in the cylinder.

[Biodiesel300TD]

Black smoke is unburned fuel, but is also carbon build-up burning off. Carbon builds up inside these engines, and it is healthy for them if once in a while you do a wide open throttle acceleration while getting on the highway to get the RPM up high which burns out all that carbon.

[Missouri240D]

lay off the gas, hit the gas. got it. just kidding. thanks fellas.

[yellowbenz]

At night, you may see sparks accompany the smoke if it's carbon burning off. Humorous post about this several years ago.