The pooja of the new car itself is superstition at it's best. I find it so weird when seeing the pictures of new car poojas where the priest perform the rituals on the car as if it is an idol. The rituals are meant to worship the god with symbolic idols. Of course there is "vahana pooja" (vehicle pooja) in hindu practices, but that is actually worshiping the 'carriers' of God like Garuda, Nandi etc. not any human made vehicle.