The most probable cause is combustion of a rich mixture of fuel.
Black smoke coming out of the exhaust of a car is usually due to oil being burned in the engine's cylinders. This can be caused by a worn piston ring or rings.
Black smoke from an engine is caused by unburnt fuel.
YES
WHERE IS THE SMOKE COMING FROM ?
White smoke is usually vaporized coolant. You may have a blown gasket or a crack somewhere.
Your oil is probably leaking. If the car is old, then it's likely to be scrap!
Smoke could be coming from the vents of your car for a number of reasons. You may have an internal car fire.
Black smoke in your exhaust is a sign of your car burning oil. You should have a qualified mechanic inspect your car and make the proper adjustments.
Blue smoke, burning oil. (tired) White smoke, burning coolant. (bad head gasket) Black smoke, excess gasoline (flooding).
An Rx7 is a model of a car that Mazda makes. All cars can smoke lightly through the exhaust system. If the smoke that is coming out becomes excessive or black consult a mechanic.
Shut the car off and get out. Something is broken and if its producing smoke, it could catch on fire.
The only thing that causes smoke in a car is something burning. Steam or vapor coming from the air conditioner can also look like smoke. More detail especially where the smoke seems to be coming from would be helpful. This sounds like something that needs immediate attention and you should not be driving the car if you cannot find the origin of the smoke.