The Death Car
A young man was distraught after his girlfriend broke up with him. He had thought that the cool new silver Corvette he'd gotten for his 18th birthday would be enough to keep her with him, despite his occasionally-wandering hands and eye, but that turned out not to be the case. To teach his girl a lesson, he parked the car in front of her house, filled all the chinks in the car's floor with steel-reinforced concrete, and then, with the motor running, ran a hose from the exhaust pipe and in through the window.
This occurred in August, but the young man's death wasn't discovered until the following December when the ex-girlfriend finally got sick of his "stalking" her and, with restraining order in hand, went out to the car to tell him to beat it.
The Corvette was still in perfect condition, aside from being out of gas and covered in parking tickets. The young man's family sold it to a used car dealer, who cleaned it up and put it in a place of honor on his lot. It was eventually purchased by a middle-aged man with a combover who thought it would be just the thing for his image.
The car's new owner had it for only a couple of days when he noticed a particularly horrible stench -- the smell of death. He bought an air freshener, drove with the windows open, and did everything else he could think of, but the smell would not go away. That was when, speeding down the highway, he noticed the young man's corpse, still in the passenger seat. He stuck his head out the window to call for help, only to have it knocked off by a passing truck.
A young man was distraught after his girlfriend broke up with him. He was a relief fullback on the high school football team, knew all the best places to pick up after-market racehorse-strength steroids, and had a brain like a steel sieve, but still she dumped him half way through their first date without having sex with him or anything.
Well, he was going to show her!
He parked his car on the street in front of her house and, with the motor running, ran a hose from the exhaust pipe through the window. Later that night, with gas running low, he was really hungry and had a bad headache. He was just starting to wonder why he wasn't dead when his girlfriend's father pulled up in a cement mixer and, for some reason, dumped a load of concrete in through the convertible's open top, killing him almost instantly.
Behind the Legend
The "stinky car" legend exists in two significantly different strains, one serious and one humorous, examples of which are above.
The humorous version is much more recent. It apparently came to life when the original legend merged with a 2004 news story about a hapless teenager who tried unsuccessfully over the course of several days to asphyxiate himself with the "fumes" from his parents' prototype fuel-cell automobile.
In its more serious form, the "smelly car" legend has been around since at least the 1920s. It has been told about young men killing themselves for a variety of reasons, and the car involved has been said to be a Model-A, Cadillac, Jaguar, PT Cruiser, or -- in a variation featuring Luke Skywalker becoming despondent after finding that he had naughty thoughts about his own sister -- a landspeeder. There is also a variation in which a man kills himself by locking himself in a restaurant's walk-in refrigerator, and the restaurant's owner only realizes where the horrible stench is coming from when the dead man has been butchered and half eaten by an ignorant assistant.
In the 1950s, a folklorist believed he had traced the "noxious car" legend back to its roots -- a New England tale of a smelly rocking chair in which a depressed young man had rocked himself to death. Unfortunately, that tale lacks a number of significant elements of the automotive tale (e.g., a car), and so is unlikely to be its progenitor.
More likely, the story is intended as a putdown for annoying folks who recently purchased a car and won't shut up about it having a "new car smell."