Dude, why is my car?
FAQTA is pleased to learn that someone with "dude" in her/his vocabulary worries about philosophical matters.
The question why your car is, or exists, can be given (1) a causal explanation, (2) a functional explanation or (3) an intentional explanation:(1) Your car exists since some event or another caused the Big bang around 14 billion years ago, which in turn set a chain of events in motion that inter alia led to the creation of earth, the evolution of man and ultimately the existence of your car.
(2) Your car exists in order to transport you to work. (Assuming you have one.)
(3) Your car exists since someone had some reason or another for building it.