88 GT n loven it....

I was wondering what does it mean when my car throws black smoke when im on the highwaythis doesnt happen all the times it once n a while when i downshift andstep all the way on the gas pedal it throws black smoke so i was wondering what does that mean the car feels that is still runing very strong although it throws a little bit of black smoke ? anyone know what this might be ?

94ford5liter

could mean a number of things, you should definitely look into it. Maybe the car is just running really bad, or it could also mean your piston rings are done. Its really hard to say with smoke like that without more details.

PRO50SC

Black smoke is a sign of the engine running too rich!!