Could we use Co2 to power our cars?And since it is bad for the enviroment the car will imit something good from the car. And we can get the Co2 from the air. The Co2 could replace gasoline.

C02 is the result of burning. Gas supplies to the Carbon portion, while air supplies the Oxygen. In order for it to be used as fuel, the CO2 would have to combine with something to release energy. By itself, it's used to extinguish fires.

That doesn't mean CO2 is necessarily bad for the environment. In fact, plant life needs C02 to grow (google photosynthesis). There are those who believe that excess CO2 will cause a spurt in plant growth that will be good for the environment.