Do cars produce CO2?

Do cars produce CO2?
Yes.
Cars burn up petrol, diesel, LPG and so forth.
When burning hydrocarbons, they will react with oxygen to form water and CO2.
Unfortunately this is not the case. Not all fuel is converted to CO2 and H2O.
Some is converted to CO (carbon monoxide, very poisonouss) and some doesnt burn at all or is converted to a shorter chained hydrocarbon.

Its the car exhaust catalyst's job to convert these (and other) substances to CO2.