In Real Life, gasoline is a very refined and volatile product. Creating usable gasoline (or any other petroleum-based fuel) requires extracting petroleum from the ground, and separating the various elements of it by carbon chain in an oil refinery. Gasoline is meant to be used soon after production, and has a usable shelf life of about three to five months. With fuel stabilizer you can extend that shelf life out several times as much but no matter what you add or how you store it, storing it for more than two years is out of the question. After that, it starts to break down and vaporize. The non-volatile component left behind is a useless gunk usually called "varnish" in the trade, though it's not exactly the best thing to waterproof your wooden table that has to be cleaned out of the engine. But in today's modern world of nigh-ubiquitous motor vehicles, this is rarely a real problem.
In fiction, on the other hand, gasoline is just an eternally lasting fuel liquid that can sit anywhere for any period of time, and be as usable as the day it was refined. This is common in post-apocalyptic fiction, where everyone is driving around in cars and scrounging for precious drops of gas long after any refineries would stop producing. If such a post-apocalyptic world did occur in reality, we would be able to drive around for a few months, but afterwards, unless someone got a refinery up and running again, every gas-powered vehicle on the planet would be 100% useless.
This is basically a Sub-Trope of Ragnarök Proofing, in that something leftover from the old society still works despite it being impossible. Sometimes this is handwaved through Applied Phlebotinum, but often it just assumes that audiences think gasoline is eternal... probably because audiences learned it from them.
This trope doesn't only happen in post-apocalyptic fiction either. Sometimes people find a vehicle that goes for years or even decades unused, and they turn the key and it immediately turns on and works perfectly. Ignoring the fact that OTHER parts of the vehicle would need restoration, the gasoline still in the tank would be completely unusable and that transport is going nowhere.
Often overlaps with No Bikes in the Apocalypse, which is about a different piece of transportation technology not being used even though it can be.
- Dimension W takes place in a future where free energy has been realized so there's not an energy crisis, but protagonist Mabuchi Kyoma refuses to use the coils that contemporary energy is grounded in for his own reasons. Part of his Establishing Character Moment is to take a job on the promise that he would be paid in half in cash and half in gasoline, the latter for his car, practically the only one of its kind left.
- Uncle Scrooge: In "Chugwagon Derby" by Carl Barks, Scrooge reveals that as young man he bought a horseless carriage when they were first becoming available. However, after discovering that he could walk faster than the car could drive, he hid it away in a barn; afraid that people would laugh at him for his foolishness. However, after Donald shows him how you can make money in vintage car contests, he goes and hauls it out from under the pile of old harness where it is hiding. He comments that it runs on a mixture of kerosene and whale oil and, to his delight, he discovers there is still $1's worth in the tank. The fires the car up and it starts immediately. As the story was first published in 1961, the car and fuel would have had to have been sitting there for about 60 years.
- In the Kim Possible fic "Alone, Together", Kim and Shego are accidentally stranded in an alternate universe just like the real world but with no other people. They live there for two decades before finding a way to get back home, scavenging fuel supplies for power and transportation the entire time.
- Battlefield Earth: Jet fighters still work after a millennium without service, including apparently the fuel. Being less volatile than gasoline, jet fuel really does have a much longer shelf-life than gasoline, but even that's only a few decades.
- The Book of Eli. It's been thirty years since a nuclear war that wiped out civilization, yet vehicles are still running on gasoline from before the apocalypse.
- Five Graves to Cairo is set in 1942. Rommel tells Bramble that the Germans hid supplies in Egypt way back in 1937 while pretending to mount an archaeological expedition. The food and spare parts might still be good, but five years is way too long to store gasoline even under the best conditions. Gasoline will break down in two years, tops.
- 48 Hrs. is another non-apocalyptic/post-apocalyptic example. While Jack and Reggie watch from a distance, Luther comes back to the Parking Garage where Reggie's car has been for the past two and a half years to collect it. The attendant sort of lampshades this trope when, after Luther asks how the oil and battery in the car are, he sarcastically responds that they take care of that every year.note Not only does the car function, Luther is able to start it right up.
- I Am Legend: Neville, the last human in the abandoned New York City, fuels his car by manually pumping out gasoline from abandoned gas stations. Like everything else in the city, these gas stations have been untouched for three years, with their last recorded price being 6 dollars a gallon!
- Into the Forest has a downplayed example. There's never any concern about whether the sisters' gasoline will go bad, though this may simply be due to their ignorance. After at least a few months, it still powers the generator perfectly fine. After at least 15 months of storage, the gas is still volatile enough to be set ablaze with a spark, which might be possible.
- I, Robot: Detective Spooner keeps a 2004 MV Agusta F4-SPR 750 crotch rocket in a storage unit, which he and Dr. Calvin use to get around during the robot uprising (his unmarked car was totaled earlier in the film). He's established as a Fan of the Past and has apparently kept it maintained, but where he gets the fuel from is a question mark: Dr. Calvin is fearful of the bike since it's gas-fueled — she notes gasoline's tendency to explode — strongly implying that it's no longer commonly available in the film's 2035.
- Jurassic World: When Zach and Gray find the remains of the original Jurassic Park they also find the jeeps in the garage. The fuel inside is still usable despite it sitting there for over 20 years.
- The Last Chase centers around a retired race car driver in a world where the oil wells dried up twenty years previously building a sports car in his garage and driving it the length of the continental US. That's a three thousand mile trip, requiring at least a hundred gallons of gas (likely a lot more given that he's driving a sports car rather than something fuel efficient), and nowhere does the film explain how he managed to find that much usable gas more than a decade after all the gas stations were shut down. Even if he could pump the dregs from abandoned stations, it wouldn't be of good quality, and the Porsche he was driving requires high octane fuel.
- Another World War II thriller, Northern Pursuit, has German commandos infiltrating Canada in 1943 so they can assemble a plane hidden in the far north before the war. Naturally, the plane starts up and flies.
- In Rats: Night of Terror, the gang finds a working flamethrower and several working motorcycles in the city, despite it being more than 200 years since any of those things have seen any use.
- Sleeper: Miles and Luna find a Volkswagen Beetle that has been in storage for 200 years. It starts right up and they drive it for a considerable distance with no problems.
- In Star Trek Beyond, Kirk finds a fictional Hilts PX70 dirt bike in the cargo bay of the crashed USS Franklin, and soon rides it to the rescue of his crew. The motorcycle is at least a hundred years old.
- Waterworld has interesting take on this trope, as the vehicles run on oil, not gasoline. Crude oil does have a longer shelf life, about ten years, but no vehicle in the world would use something so unevenly mixed as fuel (and a post-apocalyptic society couldn't build something that could). The setting is also implied to be hundreds of years, long past when those extra ten years would matter.
- Doesn't apply to Zombieland, which is set a mere two months after the zombie-induced breakdown of civilization, but it does apply to the sequel, which skips five years ahead.
- Battlefield Earth is an especially egregious example. It has the protagonists finding and using 20th century fighter jets 1000 years after aliens took over Earth and drove humanity back to the Stone Age. Even if the planes themselves had somehow been perfectly preserved, it beggars the imagination that there would still be usable jet fuel around.
- Death Lands hand waves (partially) with the fact that one of the pieces of Lost Technology that is lying around is a mixture of gasoline that is superior to regular petrol, taking much longer to burn (a regular tankful goes around five times longer) and has a different chemical mixture (which probably includes some kind of preservation agent). However 1) the series happens a hundred-plus years After the End (which should make even the best petrol preservative be on its last legs realistically) and 2) oftentimes the cars or generators that appear use scavenged fuel from regular pumps.
- In The Stand, characters keep driving cars many months — in the extended edition, a whole year — after The Plague wipes out 99 percent of humanity.
- Arrow. In the Season 2 flashbacks on Lian Yu, our heroes get both a World War 2 Japanese submarine and the Kaiten manned suicide torpedoes it's armed with running again.
- Early during the second season of Lost, a few of the survivors find an old Volkswagen van that crashed and was abandoned deep in the island's jungle and is as decrepit as you would expect it to be. A whole episode is spent trying to make it roll (and it eventually does, even becoming a Chekhov's Gun for the season finale) but the main concern of the characters seems to be the battery, not the fact that it's been lying in a jungle for so many years (roughly since The '70s, when Benjanin Linus made it crash by killing his abusive father) that the gas must have long since gone bad. Probably another of the mysteries of the Island — just like the beer that was inside the van for the same amount of time yet is still fit to drink.
- The Last Man on Earth takes place two years after a virus wipes out most life on Earth, yet the main characters are shown driving cars constantly. There is at least one mention of how long gasoline can last, but it never becomes a serious problem.
- The Last Train has a group of people who were cryogenically frozen during the Apocalypse wake up after forty years has passed, then go out and find a Mercedes Sprinter Van which starts and runs just fine pretty much on first turn of the key.
- The Twilight Zone (1959) episode "The Rip Van Winkle Caper". Four men enter suspended animation in a cave after a gold robbery and sleep for 100 years. When they wake up, their car starts up and can be driven with no problem.note
- Confirmed, then averted in The Walking Dead. The first couple of years, they have no problems, with almost any car they come across starting right up. After a time jump to about ten years after the apocalypse, they're back to horses.
- Aftermath!, Scenario Pack 1: Into the Ruins. One vehicle used by some Non Player Characters is a jeep that runs on gasoline. The problem: the nuclear war and biological holocaust that destroyed civilization occurred twenty five years before the scenario begins, so any gasoline they find should be useless.
- Explicitly handwaved in Apocalypse World, whose rulebook mentions towards the end that Real Life gasoline would evaporate within months of the apocalypse, but the author still wanted to include Cool Cars and Cool Bikes in his game.
- Subverted in GURPS After the End, in which gasoline is no longer useful. Instead, rules are given for converting vehicles to use ethanol, biodiesel, or gasifiers.
- In Ashes 2063, 70-something years after the apocalypse, any gas you find is still perfectly usable, though it is difficult to find and/or produce. Dialogue with NPCs clarifies that most internal combustion engines were re-tooled to work with plant-based biofuel,note which is much easier to make and every settlement has a decent stockpile of.
- Fallout 4 has cans of gasoline still usable as crafting materials for the "oil" category going on two centuries After the End. This is in spite of the Fallout setting being Post-Peak Oil and suffering a major energy crisis by the time of the Great War (and the fact that "oil" seems to be a lubricant rather than a fuel in many applications, when gasoline doesn't make much of a lubricant).
- Far Cry: New Dawn subverts this trope; background material specifically mentions that most if not all stored gasoline has deteriorated well past usable condition in the 17 years after the Collapse; as a result, combustion engines in the post-apocalypse Hope County run on what is implied to be ethanol-based fuel, to the point that even murderous raider gangs will carefully and meticulously keep a sizable storage of vegetables for processing into fuel — which they typically steal from the locals. Many of those who were alive before the Collapse will even wistfully comment how the converted ethanol-based engines "just don't have the same sound" as the old gasoline engines.
- Horizon Zero Dawn averts this for the most part, as the machines continue to refine Blaze for fuel. But the Corruptors and Deathbringers have no excuse as they're resurrected remnants of the original Faro swarm that wiped out all life 1000 years ago and their fuel should have long been rendered useless.
- In The Last of Us, Bill gives Joel some siphoning equipment to get gasoline out of cars for his truck he just gave him. Since the game takes place 20 years after the end of civilization, the gasoline in those cars should be too old to be usable.
- In Episode 5 of The Walking Dead Season 2, Kenny suggests to Clementine and Molly to siphon gas from the abandoned vehicles, even though they should be unusable. Episode 1 of Season 3 has Javier's party scavenging cars for gas years after that.
- In The Simpsons episode "The Principal and the Pauper", Armin Tamzarian (the former Principal Skinner) goes to the storage locker where he keeps all his stuff from his rebel days. His old motorcycle is in there, and despite being untouched for well over 40 years, it still works perfectly and gets Skinner to Capitol City.
- In Regular Show episode "The Night Owl", a vintage muscle car is put up as the prize in a Radio Contest. Two thousand years later, it starts up without a hitch when the gang need to use it to escape from the authorities.