CAR: 1994 Chevy Cavalier. ISSUE: Driving down

For the smoke to occur in the engine compartment it has to be something that occurred external to the engine or an external leak from the engine. White smoke would have been steam and suggest a blown gasket that allowed water to exit the engine. Assuming it was not something that burned it would point to a leakage of oil or perhaps a belt. Two things I would check are the belts and the engine compression. An external oil leak on a hot engine could have made the black smoke and may not show up when the engine is cool. If it is an oil leak you may be able to find out where by putting some paper under the engine and turning the engine over enough to create a drip on the paper.

Also try to remember if you smelled anything when the problem occurred.

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Check underneath the car for exhaust manifold and pipe damage or cracks. Look for black spots around the flange areas, fittings along pipe connections leading to the catalytic converter. Sounds like your cat may have collapsed internally and blocked your exhaust. This will cause high exhaust back pressure and it will need a way out if not through the cat it will cause the pipes to crack at a weak point and give you the black carbon cloud you had.
Have the fuel pressure checked also, pump may have failed starving engine of fuel causing backfire and bucking then no start.