The nose, pharynx, larynx, trachea and bronchi all work like a system of pipes through which the air is funnelled down into our lungs. There, in very small air sacs called alveoli, oxygen is brought into the bloodstream and carbon dioxide is pushed from the blood out into the air.
And, just to clarify, the kitty litter in your trunk, to be used for traction, needs to be taken out and spread around your tires. Most cars are front wheel drive, so the extra weight alone in the back ain't gonna do you much good.
Do a health check. The first step is to take your kitty to your vet for a thorough physical exam. Several medical conditions may result in a cat not using the litter box, so you'll want to rule these out before looking at other potential causes.