Is It Safe to Drive With a Bad Ignition Coil?
You generally should not drive with a bad ignition coil. A brief, gentle drive to a nearby repair shop may be possible, but continuing to drive risks sudden loss of power, catalytic converter damage, poor fuel economy, and safety hazards. Below, we explain how ignition coils work, the risks of driving with a misfire, what to do immediately, and how to decide whether you can limp to a repair facility or should arrange a tow.
Contents
What an Ignition Coil Does—and Why It Matters
The ignition coil transforms your car’s 12-volt battery power into the high voltage needed to fire the spark plugs. In modern vehicles, each cylinder typically has its own “coil-on-plug.” When a coil fails, that cylinder misfires—fuel doesn’t burn properly, the engine runs rough, power drops, and raw fuel can enter the exhaust, overheating and damaging the catalytic converter.
Is It Safe to Drive?
Automakers and repair professionals generally advise against driving with a known misfire or bad coil, especially if the check-engine light is flashing. A short, low-load trip to a nearby shop may be acceptable if the vehicle is still controllable, but continued driving can escalate repair costs and create safety risks.
How to Recognize a Failing Ignition Coil
The following list outlines common symptoms drivers notice when an ignition coil is failing or has failed.
- Rough idle, shaking, or vibration—especially at stoplights
- Hesitation, stumbles, or lack of power under acceleration
- Check-engine light on; often flashing during active misfire
- Poor fuel economy and exhaust smell of unburned fuel
- Hard starts or stalling
- OBD-II codes such as P0301–P0308 (cylinder-specific misfire) or P0351–P0358 (coil circuit fault)
If one or more of these signs appear, treat the condition as urgent: misfires can quickly damage expensive exhaust components and compromise drivability.
Immediate Risks of Driving With a Bad Coil
The points below explain what’s at stake if you continue to drive with an active misfire.
- Catalytic converter damage from overheating due to unburned fuel
- Raw-fuel contamination of engine oil, accelerating wear
- Loss of power that can make merging or crossing intersections hazardous
- Increased fuel consumption and emissions (emissions-test failure)
- Potential for further damage to spark plugs, ignition modules, and oxygen sensors
Because catalytic converters are costly and essential for emissions compliance, preventing converter damage alone often justifies towing rather than driving.
Can You Limp It to a Shop?
In limited circumstances, a short, cautious drive to a nearby repair facility might be reasonable. The following conditions can help you decide.
When It Might Be Acceptable to Drive Briefly
Consider these factors before attempting a short drive.
- The engine runs relatively smoothly and the misfire is intermittent, not constant
- No flashing check-engine light (a steady light is less urgent than a flashing one)
- Trip is very short, surface streets only, with minimal traffic and low speeds
- No burning smells, loud backfires, or severe vibrations
- You can avoid heavy acceleration, hills, towing, or high loads
If all of these conditions are met, a gentle drive of a few miles to a trusted shop may be tolerable—but proceed with caution and be prepared to stop if symptoms worsen.
When You Should Not Drive
The red flags below indicate you should shut the vehicle off and arrange a tow.
- Flashing check-engine light (indicates catalyst-damaging misfire)
- Strong fuel smell, loud pops/backfires, or visible smoke
- Severe loss of power, stalling, or inability to maintain safe speeds
- Shaking so intense that the vehicle is hard to control
- Overheating or additional warning lights (oil pressure, temperature)
Driving under these conditions can quickly turn an affordable ignition repair into a much larger bill for exhaust and engine damage—and may create a safety hazard.
What to Do Right Now
If you suspect a bad ignition coil, take the following steps to limit damage and get accurate diagnosis.
- Scan for codes: Use an OBD-II scanner (many parts stores offer free scans) to check for misfire or coil circuit codes.
- Assess drivability: If the light is flashing or the car is hard to control, stop and arrange a tow.
- Avoid heavy load: If you must drive a short distance, keep speeds and RPM low and avoid hills and hard acceleration.
- Schedule prompt repair: Misfires should be addressed immediately to protect the catalytic converter.
- Replace related wear items: Coils often fail alongside spark plugs or boots; replacing these together can prevent repeat issues.
Following these steps helps contain costs and prevents compounding damage while you arrange professional service.
Diagnostic Clues and Common Causes
These pointers can help you or your technician confirm whether an ignition coil is the culprit and identify related issues.
- Code mapping: P030X points to the cylinder; P035X points to the coil or its circuit for that cylinder
- Swap test: Moving a suspected coil to another cylinder and seeing if the misfire follows can confirm a bad coil
- Inspect spark plugs and boots: Worn plugs or cracked boots can stress coils and cause repeat failures
- Check connectors and wiring: Corrosion, loose pins, or rodent damage can mimic coil failure
- Moisture and oil contamination: Leaking valve cover gaskets or recent engine washing can trigger coil misfires
Because multiple parts interact in the ignition system, a thorough inspection prevents replacing the wrong component or missing an underlying cause.
Repair Costs and Options
Costs vary by vehicle and parts quality; this breakdown offers typical ranges.
- Individual coil: About $50–$150 per coil for many mainstream cars; premium or high-output coils can cost more
- Coil pack (shared unit): Often $150–$400 for the part, depending on design
- Labor: Commonly $50–$150, but can be higher if access is difficult
- Spark plugs/boots: $40–$150 for parts; advisable to replace with coils if age or wear is evident
- Catalytic converter (if damaged): $800–$2,500+ per converter on modern vehicles
Replacing a failing coil promptly is usually a modest repair; delaying can multiply costs, especially if the catalytic converter overheats and fails.
Special Cases and Exceptions
Not all powertrains use ignition coils in the same way, and some don’t use them at all.
- Diesel engines: No ignition coils; misfires arise from other causes (injectors, compression, glow plugs, etc.)
- Hybrids: The engine still uses coils when running; the electric motor can mask symptoms at low load but misfires still risk converter damage
- Electric vehicles: No coils or spark plugs—this question doesn’t apply
- Turbocharged engines: Misfires under boost can be more severe; avoid load and address immediately
If you drive a diesel, hybrid, or performance vehicle, the urgency and diagnostic path may differ, but the rule remains: don’t ignore misfires.
If You Must Drive Briefly: Practical Tips
If circumstances require a short drive to a nearby shop, these measures help minimize harm.
- Keep speeds low and avoid highway or steep grades
- Accelerate gently and maintain steady throttle
- Avoid towing or heavy cargo
- Monitor for worsening symptoms and be ready to pull over
- Do not continue driving if the check-engine light flashes or the car bucks violently
These are temporary tactics to reach service safely—not a solution. Prompt repair is still essential.
Bottom Line
Driving with a bad ignition coil is risky and can quickly become expensive. If the check-engine light is flashing, or the car runs poorly, stop and tow the vehicle. If symptoms are mild and conditions are safe, a short, gentle trip to a nearby shop may be acceptable—but act quickly to avoid catalytic converter damage and higher repair bills.
Summary
You should avoid driving with a bad ignition coil. A brief, low-speed drive to a nearby repair shop may be possible if the car remains controllable and the check-engine light is not flashing. Continued driving risks catalytic converter failure, increased repair costs, and safety concerns. Scan for codes, minimize load if you must move the car, and schedule immediate diagnosis and repair—often a comparatively inexpensive fix if handled promptly.
How expensive is it to fix an ignition coil?
Average Cost for Ignition Coil Replacement
The average cost to replace an ignition coil is between $230 and $330, according to RepairPal. This cost includes both labor and parts. Labor is estimated at $75 to $100, while the cost of parts typically ranges from about $155 to $230.
What happens when an ignition coil goes bad while driving?
If an ignition coil fails while driving, the engine will likely misfire, causing the vehicle to lose power, jerk, or vibrate, and the Check Engine light may illuminate. Prolonged driving can lead to severe engine damage, including catalytic converter failure from unburnt fuel, cylinder wall damage, piston ring problems, and bearing failure due to oil dilution. It is best to pull over to a safe location as soon as possible.
Immediate Symptoms
- Engine Misfires: The cylinder won’t receive the spark it needs to ignite the fuel and air, causing the engine to misfire.
- Loss of Power: The vehicle will feel sluggish or lose power, especially when accelerating.
- Rough Engine Operation: You may notice jerking, vibrations, or rough idling.
- Check Engine Light: A faulty ignition coil will trigger the Check Engine light, and a diagnostic code related to the malfunction will be stored.
- Stalling: In extreme cases or if the last working coil fails in a single-coil vehicle, the engine could shut down entirely.
Potential Long-Term Damage
- Catalytic Converter Failure: Opens in new tabUnburnt fuel can enter the exhaust system and ignite in the catalytic converter, causing extremely high temperatures and damaging it, according to Firestone Complete Auto Care.
- Cylinder Damage: Opens in new tabUnburnt fuel can wash oil from the cylinder walls, leading to excessive wear on the cylinder and piston rings.
- Oil Dilution: Opens in new tabFuel can mix with the engine oil, diluting it and reducing its lubricating properties, which can lead to bearing failure.
- Engine Bearing and Crankshaft Failure: Opens in new tabThe increased stress on the engine from the non-firing cylinder and the lack of proper lubrication can cause catastrophic damage to bearings and the crankshaft.
What to Do
- Pull Over Safely: As soon as you notice symptoms, find a safe spot to pull over.
- Do Not Delay Repairs: Driving with a failing ignition coil can quickly escalate from a minor inconvenience to an expensive repair.
- Consult a Mechanic: Have the vehicle inspected by a professional to diagnose the issue and replace the faulty ignition coil promptly.
How long can you drive with a broken coil?
Can you drive with a broken coil spring? No, you cannot drive your vehicle if the boil spring is broken. It is illegal to drive a vehicle that isn’t safe and road legal – and having little or no control over a vehicle when it turns or drives over uneven surfaces can lead to dangerous situations.
How far can you drive with a misfiring engine?
In most automobiles, you could theoretically travel thousands of miles with a misfiring cylinder. The engine’s other cylinders will continue to produce power. So, even if you shake and stall along the wall (and don’t acquire much speed or acceleration), the car will still operate.
