can a misfire start a car on fire

[Claire]

Yes, a misfire can potentially start a car on fire, but it is not the most common cause. The primary danger lies not in the misfire itself—which is an interruption in the engine's combustion cycle—but in the unburned fuel that can result from it. When a cylinder misfires, raw gasoline is often dumped into the exhaust system. This hot fuel can then ignite on the extremely high-temperature surfaces of the catalytic converter, which is designed to burn off pollutants and can reach temperatures exceeding 1,400°F (760°C).

The risk increases significantly if the misfire is caused by a failure in the ignition system, such as a faulty spark plug wire or a cracked ignition coil. A leaking fuel injector that causes a misfire also presents a direct fire hazard by spraying fuel onto hot engine components. While modern vehicles have numerous safety features, ignoring a persistent misfire, especially when accompanied by a smell of gasoline or visible smoke, dramatically raises the risk of a fire starting.

According to the National Fire Protection Association (NFPA), vehicle fires are a serious issue. The data below illustrates the scale and common causes, with mechanical failures being a leading factor.

Year	Estimated Vehicle Fires in the U.S.	Civilian Deaths	Civilian Injuries	Direct Property Damage (in USD)	Leading Cause Category
2021	173,000	650	1,500	$1.9 Billion	Mechanical Failures
2020	181,500	630	1,550	$1.8 Billion	Electrical Failures
2019	189,500	650	1,600	$1.7 Billion	Collisions
2018	194,000	675	1,650	$1.8 Billion	Mechanical Failures

If your car is misfiring—characterized by a rough idle, loss of power, jerking acceleration, and the check engine light flashing—it is a clear sign to stop driving and have it inspected immediately. Addressing the root cause, whether a bad spark plug or a faulty sensor, is a critical safety measure.

[VonOlivia]

Absolutely, it can. I’ve seen it. A constant misfire means gas isn't burning where it should—in the cylinder. That raw fuel gets pumped into the exhaust, right into the red-hot catalytic converter. It’s like throwing gasoline on a lit grill. If you have a flashing check engine light and a smell of gas, don’t gamble. Get it towed to a shop. It’s not worth the risk.

[VonAmelia]

From an engineering standpoint, the probability is low but non-zero. The misfire is a symptom of incomplete combustion. The hazard arises when unburned hydrocarbons exit the combustion chamber and encounter a sufficient ignition source, most commonly the catalytic converter. Modern engine control units will attempt to compensate, but a severe, unresolved misfire presents a measurable fire risk. The key is to treat a misfire as a serious fault requiring prompt diagnosis.

[VanVincent]

Think of it this way: a misfire is a warning sign, not the firestarter itself. The real problem is the leftover gasoline. Your catalytic converter gets incredibly hot to clean the exhaust. If a lot of unburned fuel hits that super-hot surface, it can ignite outside the engine. So while a single hiccup won't cause a fire, ignoring a rough-running engine for weeks on end is asking for trouble. Get it checked out.

[DeGabrielle]

It’s a chain reaction. A bad spark plug or coil pack causes a misfire. Unburned fuel flows into the exhaust. The catalytic converter, which runs at over a thousand degrees, tries to burn this fuel off. Under the right (or wrong) conditions, this can cause an external fire, especially if there are oil or fuel leaks present. It’s a perfect storm of small issues leading to a big problem. Never ignore a flashing check engine light.