> **Quick Answer:** Pull over if your check engine light is flashing, the car is shaking hard, you smell burning, or power is dropping fast. A steady misfire with no other warning signs gives you a short window to exit safely, but do not push past the next exit hoping it clears up. Engine misfires can turn into catalytic converter damage or a full breakdown within minutes of ignoring them.
## Should I Pull Over Right Now or Can I Drive to the Next Exit?
Exit at the first safe opportunity, but you do not need to slam on the brakes and stop on the shoulder this second unless something else is wrong. A misfire is your engine failing to fire one or more cylinders on cue. The key question is whether it is an isolated rough-running condition or a sign that something is failing fast.
Here is how to read it while you are still moving:
- **Flashing check engine light:** Pull over immediately. A flashing CEL almost always means an active misfire severe enough to damage the catalytic converter. This is not a "drive to the shop" situation.
- **Steady check engine light plus rough idle or surging:** Get off at the next exit. Drive slowly on the surface streets to a parking lot and assess before continuing.
- **Rough running but no warning light yet:** Still get off as soon as you can. The light may not have triggered yet, but something is wrong.
- **Sudden loss of power with shaking:** Treat this like an emergency. Signal, ease to the right lane, and use the shoulder if you cannot reach an exit.
## What Does an Engine Misfire Actually Feel Like at Highway Speed?
You will feel it as a rhythmic or random jerk, stumble, or shudder, especially under acceleration. At freeway speeds, it often shows up as a hesitation when you press the gas or a vibration through the steering wheel and seat. Some drivers describe it as the engine "skipping" or briefly cutting out.
Common causes on a highway include a fouled or failing spark plug, a failing ignition coil, a vacuum leak, or a clogged fuel injector. A single bad coil-on-plug ignition coil, like the type used on a Ford 5.4L Triton V8 or many GM V6s, is one of the most common freeway misfire causes and will kill power on one cylinder entirely until replaced.
If you smell raw fuel or burning plastic along with the misfire, treat that as urgent. Raw unburned fuel passing through to a hot catalytic converter can cause serious damage or, in rare cases, fire.
## Is It Safe to Stay in Traffic or Do I Need the Shoulder?
If the car is still making power and responding to the gas pedal, stay in the right lane and get to the next exit. Do not try to limp 15 miles on a misfiring engine. Pick the next exit, not the one you prefer.
If the power drops to the point where you cannot maintain safe speed, or if the shaking becomes violent, move to the shoulder. Hazard lights on, full stop, stay inside with your seatbelt on if traffic is passing at speed. The shoulder of a busy freeway is genuinely dangerous. Check out [how long you can safely wait on the side of a highway for a tow](/how-long-can-you-wait-on-side-of-highway-for-tow/) before deciding whether to stay with the car or move away from it.
## What Should I Do Once I Am Pulled Over?
Turn the engine off. Do not keep it running to "see if it smooths out." You have already confirmed it is misfiring and continuing to run it risks damaging the catalytic converter or overheating a cylinder.
Do this:
1. Hazard lights on before you even stop fully.
2. Get as far right as po
*Photo: Pexels*
ssible, ideally past the white fog line onto a paved shoulder.
3. If you have them, set road flares or reflective triangles 50 to 100 feet behind the car.
4. Call your roadside assistance provider or a tow. A misfiring car needs a diagnostic scan (OBD-II codes P0300 through P0308 cover cylinder-specific misfires) before it is safe to drive again.
Do not attempt to diagnose spark plugs or coils on the shoulder of a freeway. That is a job for a parking lot or shop.
If you are weighing whether your roadside coverage is worth using, [State Farm Roadside Assistance vs AAA](/state-farm-roadside-assistance-vs-aaa-which-is-better/) breaks down which plan actually gets you help faster in a situation like this.
## Will Driving on a Misfire Ruin My Engine?
It can, depending on how long and how hard you push it. The most immediate risk is catalytic converter damage from unburned fuel overheating the substrate inside the converter. A replacement catalytic converter on most vehicles costs $500 to $2,000 in parts alone. That is the repair you are trying to avoid by stopping now.
Beyond the converter, running on a misfiring cylinder can wash cylinder walls with raw fuel, which strips the oil film and accelerates wear. On a turbocharged engine, a persistent misfire can also cause uneven heat that damages the turbo. None of this happens in the few minutes it takes to reach the next exit. It happens when you ignore the problem and keep driving for miles.
If your check engine light was already on before the misfire started, [a flashing check engine light article](/check-engine-light-flashing-should-i-pull-over-now/) explains exactly what the difference between a steady and flashing light means for your next move.
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*Photo: Pexels*
## Common Questions
**Q: Can a misfire fix itself while driving?**
A: Sometimes a misfire caused by a temporarily fouled spark plug will clear at higher RPMs, but if it came on during highway driving, that window has already passed. Do not count on it clearing. Get off the freeway and have it scanned.
**Q: How far can I drive with a misfiring engine before real damage happens?**
A: There is no safe mileage number. A single-cylinder misfire at idle for a few minutes is far less damaging than a hard misfire under load at 70 mph. If the check engine light is flashing, even a mile or two at speed risks converter damage.
**Q: What OBD codes will a misfire throw?**
A: P0300 means random multi-cylinder misfire. P0301 through P0308 point to a specific cylinder. A $30 Bluetooth OBD-II reader can pull these codes in a parking lot in under two minutes.
**Q: Should I try to drive home or go straight to a shop?**
A: If the light is steady and the misfire is mild, a short careful drive to a nearby shop is usually fine. If the light is flashing or the shaking is severe, call a tow. Driving a hard misfire across town is how a $150 coil job turns into a $1,400 catalytic converter replacement.
**Q: Will my insurance or roadside plan cover a tow for a misfire?**
A: Yes, a misfire counts as a mechanical breakdown, which is covered under standard roadside assistance. Check whether your plan covers the full distance to a shop or just a few miles, since [GEICO's towing distance limits](/geico-roadside-assistance-towing-distance-limit/) and other insurers vary on how far they will tow you.
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*Need roadside help? Visit [Tow With The Flow](https://towwiththeflow.com/car-engine-misfiring-on-freeway-pull-over-or-keep-driving/) for real answers when your car breaks down.*
Car Engine Misfiring on Freeway: Pull Over or Keep Driving?
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