Can you drive a Subaru with a misfire?

Yes, you can usually drive a Subaru with a mild misfire to reach a repair shop, but you should not drive it long distances or at high speeds. If the misfire is severe, or if you notice smoke, overheating, or a sudden loss of power, pull over safely and seek assistance.

What a misfire means for a Subaru

In an internal combustion engine, a misfire occurs when a cylinder fails to ignite the air-fuel mixture correctly. Subaru’s lineup often uses boxer engines (horizontally opposed cylinders) with spark ignition and fuel injection. When a misfire happens, the engine runs rough, loses power, and the onboard computer logs diagnostic trouble codes. Misfires can stem from a worn spark plug, a faulty ignition coil, a clogged injector, a vacuum leak, or a mechanical problem such as low compression.

Common symptoms

These are typical signs that a cylinder is not firing properly on a Subaru.

• Rough idle or engine stumble


• Check engine light with misfire codes (P0300-P0306)


• Loss of power or hesitation during acceleration


• Engine vibration or shaking, especially at idle


• Decreased fuel economy or running rough under load

Recognizing these signs helps you decide when to seek service and prevents further damage to the engine or exhaust system.

Safety considerations when driving with a misfire

If you notice a misfire while driving, use caution and plan your next steps carefully. The following guidance focuses on safety and protecting the engine. If you encounter any of these conditions, act accordingly.

• Safely pull over at the nearest safe spot and turn on hazard lights if the car becomes hard to control


• Keep engine rpm low and drive with light throttle if you must continue to move the vehicle


• Avoid high-speed driving or sustained heavy acceleration


• Do not ignore the Check Engine or malfunction messages; treat them as a warning


• If you sense smoke, a strong fuel smell, overheating, or a dramatic loss of power, stop and seek roadside assistance

Following these steps helps minimize the risk of damage and keeps you safer while you arrange a tow or diagnostic service.

Common causes of misfires in Subaru engines

Misfires have a range of potential causes. In Subarus—especially newer models with direct injection and boxer layouts—some problems are more prevalent. Below are the most frequent culprits observed by technicians.

• Worn, fouled, or damaged spark plugs


• Faulty ignition coils or coil packs


• Clogged or failing fuel injectors; fuel delivery issues


• Vacuum leaks from hoses, intake gaskets, or PCV system


• Low compression due to head gasket, valve, or ring issues


• Sensor problems (crankshaft position, camshaft position, MAF) that affect ignition/fuel timing


• Direct-injection-specific carbon buildup on intake valves (common on some FB/FA engines), causing improper air flow and misfires


• Poor fuel quality or misfueled gasoline

Diagnosing a misfire typically involves reading codes, inspecting ignition components, testing fuel delivery, checking for leaks, and sometimes performing a compression test. Prompt diagnosis helps prevent damage to the catalytic converter and exhaust system.

Subaru-specific considerations: AWD, DI engines, and maintenance

Subaru’s Symmetrical All-Wheel Drive (AWD) and horizontally opposed engines exchange torque across wheels in ways that can influence how a misfire feels and how the car responds. Most misfires do not directly damage the AWD system, but engine misbehavior can trigger traction control events or limp modes that change handling. In the era of direct-injection engines, carbon buildup on intake valves has emerged as a notable misfire contributor in some models, making proactive maintenance and cleanings a common consumer concern.

Direct-injection and carbon buildup

Direct-injection Subarus can experience carbon deposits on intake valves, which reduces airflow and can contribute to misfires. Addressing this issue may involve intake valve cleaning or related service, particularly on engines with longer intervals between valve cleanings. Regular use of quality fuel and periodic system cleanings are often recommended to mitigate buildup over time.

What to do next

To determine the root cause of a misfire and prevent further damage, a professional diagnostic is advised. Here are the typical steps a technician will take.

• Read diagnostic trouble codes with an OBD-II scanner to identify the affected cylinder or system


• Inspect and test spark plugs and ignition coils; replace as needed


• Check fuel delivery: fuel pressure, injector operation, and fuel quality


• Inspect for vacuum leaks, cracked hoses, or PCV system issues


• Perform a compression test to assess engine health and identify potential mechanical problems

Early diagnosis and repair protect the catalytic converter, maintain fuel efficiency, and help keep the AWD system operating correctly.

Summary

A misfire in a Subaru signals that one or more cylinders aren’t firing as they should. You can usually drive a car with a mild misfire to a repair facility, but you should avoid long trips, highway speeds, and ignoring the warning signs. Prompt diagnosis—focusing on spark plugs, ignition coils, fuel delivery, and potential valve or compression issues—helps prevent costly damage to the engine and exhaust system, and preserves the performance of the AWD drivetrain. If you notice a misfire, consult a qualified technician as soon as possible, especially if the check engine light is on or you experience significant power loss, overheating, or unusual noises.

Is it expensive to fix a misfire?

The costs for this repair can range from 300 to as much as a new engine, which is approximately 6000. The shop would need to diagnose the source of the issue, as many factors could be responsible, including spark plugs, coils, injectors, wiring issues, the computer, sensors, or a failed engine.

Why would a Subaru misfire?

A misfire means that your engine isn't running as efficiently as it should be: either there's too much or too little fuel being injected into each cylinder, air is going into the wrong cylinders, or something is blocking the flow of exhaust gases out of the engine.

Is it okay to drive a car with a misfire?

No, it is not okay to drive a car with a misfire, especially if the check engine light is flashing, as this can lead to further engine damage and expensive repairs. Driving with a misfire can cause harm to the catalytic converter, lead to increased fuel consumption, and result in engine stalling or even complete engine failure. The best action is to stop driving immediately and have the vehicle towed to a mechanic for diagnosis and repair. 
This video explains what happens when you drive a car with a misfire: 56sHow to AutomotiveYouTube · Aug 17, 2021
Risks of driving with a misfire

• Damage to the catalytic converter: Unburnt fuel can enter the exhaust system and damage the catalytic converter, which is an expensive component to replace. 
• Engine damage: The misfire can cause other engine parts, such as oxygen sensors, spark plugs, and pistons, to be damaged. 
• Overheating: A misfire can cause the engine to overheat due to the disrupted balance. 
• Poor performance: You will likely experience decreased fuel efficiency, rough idling, vibrations, and potential stalling. 

What to do

• Stop driving immediately: If the check engine light is flashing, pull over as soon as it is safe and turn off the engine. 
• Do not ignore the problem: Even if the light goes off, a misfire can still be damaging your engine and should be addressed by a mechanic as soon as possible. 
• Arrange for a tow: It is best to have the vehicle towed to a trusted repair shop to prevent further damage. 

This video explains what to do when your car has a misfire: 51sDespair RepairYouTube · Oct 18, 2025

How long can I drive with a misfire?

You should avoid driving with a misfire and, if the check engine light is flashing, stop the car immediately. Driving with a misfire can cause serious damage to other expensive parts, like the catalytic converter, and should be driven for the shortest distance possible to a mechanic. 
This video explains why driving with a misfire can damage your catalytic converter: 55sOne Trick TechnicianYouTube · May 9, 2025
Why you shouldn't drive with a misfire

• Risk of severe damage: A misfire can send unburnt fuel into the catalytic converter, causing it to overheat and get damaged. 
• Other component damage: It can also harm oxygen sensors and other internal engine parts over time, leading to costly repairs. 
• Reduced power and fuel efficiency: You will experience a noticeable drop in power and poor gas mileage. 
• Potential for a breakdown: If the problem worsens, you could be stranded. 

What to do if you have a misfire

• If the check engine light is flashing: Stop driving as soon as it is safe to do so. Towing the vehicle is the safest option. 
• If the check engine light is solid: Drive the car for the shortest distance possible to a mechanic for diagnosis and repair. 
• Don't ignore it: The sooner you address the problem, the less likely you are to cause further, more expensive damage.