Can You Drive a Car With a Faulty Ignition Coil?

You can technically drive a short distance with a faulty ignition coil, but it’s unsafe and risks expensive damage—especially to the catalytic converter—so it’s best to stop and arrange repairs or a tow if the check-engine light is flashing, the engine is shaking, or there’s a strong fuel smell. In milder cases, you may limp a few miles to a shop at low speed, but continued driving is not advisable.

What a Faulty Ignition Coil Does

The ignition coil transforms battery voltage into the high voltage needed to fire the spark plugs. When a coil fails, the affected cylinder misfires, reducing power and increasing emissions. Understanding the typical symptoms helps you decide whether it’s safe to proceed.

• Rough idle, uneven acceleration, or hesitation
• Check-engine light (steady or flashing); common codes include P0301–P0308 (cylinder-specific misfires) and P0351–P0358 (coil circuit faults)
• Poor fuel economy and a raw fuel smell from the exhaust
• Backfiring, popping, or stalling under load
• Hard starts, especially when wet or after sitting

If you notice these signs, treat the car as compromised: drive gently only if necessary, and prioritize prompt diagnosis.

Risks of Driving With a Bad Coil

Operating with an active misfire can rapidly escalate repair costs and create safety hazards.

• Catalytic converter damage: Unburned fuel overheats and melts the catalyst, often within minutes of a severe misfire; replacement can cost four figures.
• Oxygen sensor fouling and failure due to raw fuel and soot.
• Engine wear: Fuel wash-down reduces cylinder lubrication, increasing ring and cylinder wear and diluting engine oil.
• Potential overheating of exhaust components; on turbo cars, misfires can spike exhaust temperatures and stress the turbocharger and catalyst.
• Stalling and reduced power, which can be dangerous in traffic or while merging.

Because these risks compound quickly, continued driving is a gamble that often costs more than a tow and a timely repair.

How Far Can You Drive?

If the check-engine light is steady and the car drives reasonably (minor stumble, no heavy fuel smell), you might nurse it a short distance—ideally a few miles—to a repair facility at low RPM and light throttle. If the light is flashing, the engine shakes violently, there’s pronounced fuel smell, or you’re losing power, stop and tow. There’s no safe “distance limit” for a misfire; the safer default is to avoid driving.

When It’s Okay to Drive Briefly (and How)

If you must move the car a short distance to a shop in mild conditions, these practices reduce risk.

• Keep engine load low: gentle throttle, lower speeds, and avoid hills if possible.
• Turn off accessories (A/C, heavy electrical loads) to reduce stress on the engine.
• Avoid high RPM and hard acceleration.
• Plan a short, direct route and maintain extra following distance.

These measures don’t eliminate risk, but they can limit damage during a brief, necessary trip.

When You Should Not Drive—Tow It

Certain red flags mean driving could cause rapid and expensive damage or create a safety hazard.

• Flashing check-engine light indicating an active, severe misfire
• Strong raw fuel smell, backfiring, or visible smoke from the exhaust
• Severe shaking, loss of power, or stalling
• Turbocharged engines under boost, or any situation requiring highway speeds or hills
• Misfire immediately after a recent plug/coil service (possible wiring/connector issue)

In these cases, a tow is cheaper than a catalytic converter or engine repair.

Diagnosis and Quick Checks

A few targeted checks can confirm a coil issue and prevent unnecessary parts replacement.

• Scan for OBD-II codes: P030X for cylinder misfires; P035X for coil primary/secondary circuit faults; check misfire counters in live data.
• Coil swap test: Move the suspect coil to another cylinder and see if the misfire code follows (e.g., P0302 becomes P0304).
• Inspect spark plugs: Look for fouling, cracks, improper gap, or oil in plug wells (often from leaking valve cover gaskets).
• Check coil boots and connectors: Look for cracks, carbon tracking, corrosion, loose pins, or damaged wiring.
• Moisture and contamination: Water intrusion or oil in plug tubes can trigger intermittent misfires.

If the misfire doesn’t follow the coil, the cause may be a spark plug, injector, compression issue, or wiring fault.

Repair Options and Typical Costs

Costs vary by vehicle, access, and parts quality. Many owners replace the spark plug and boot alongside the coil on the affected cylinder, or all coils on high-mileage engines for reliability.

• Coil-on-plug (per cylinder): $50–$150 for the part; 0.5–1.0 labor hours each in typical layouts
• Coil pack (shared): $100–$300 for the part; similar labor
• Spark plugs: $8–$25 each (standard to iridium), plus labor; boots $5–$20 each
• Valve cover gasket (if oil in plug wells): $150–$500 parts and labor, model-dependent
• Catalytic converter (if damaged): commonly $900–$2,500+ installed, depending on vehicle

Use OEM or reputable aftermarket coils; bargain coils can fail early. If oil contamination caused the failure, address leaks to prevent recurrence.

Special Cases

Turbocharged Engines

Misfires can superheat exhaust components and ignite fuel in the turbine or catalyst, risking turbo and catalytic converter damage. Avoid boost and tow if misfire is severe.

Direct-Injection Gas Engines

Raw fuel from misfires can wash cylinder walls and dilute oil more quickly; change the oil after prolonged misfire events.

Diesels and EVs

Diesel engines do not use ignition coils, and EVs have no combustion engine. For hybrids with gasoline engines, the same ignition-coil guidance applies.

Summary

You can sometimes drive a short distance with a faulty ignition coil, but it’s risky and can quickly damage the catalytic converter and other components. If the check-engine light is flashing, the engine shakes, or there’s a strong fuel smell, stop and tow. Confirm the fault with OBD-II codes and basic checks, then replace the coil, related boots, and spark plugs as needed—and fix any oil leaks to prevent repeat failures.

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 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.

How long can you drive on a bad ignition coil?

You can’t drive indefinitely with a bad ignition coil; you should only drive as far as necessary to get to a repair shop to avoid potentially damaging your engine and catalytic converter. A bad coil can cause rough engine running, loss of power, and poor fuel efficiency. Continued driving introduces raw fuel and oxygen into the exhaust system, which can overheat and destroy the catalytic converter, leading to much more costly repairs. 
Why you shouldn’t drive with a bad ignition coil:

• Engine Damage: Unburnt fuel from misfiring cylinders can wash away engine oil from the cylinder walls, leading to accelerated wear and damage to the engine’s crankshaft and bearings. 
• Catalytic Converter Damage: Raw fuel and oxygen that reach the exhaust system can ignite inside the catalytic converter, causing it to overheat and become damaged. 
• Poor Performance: You’ll experience a rough-running engine, loss of power, and reduced fuel efficiency, making your car unsafe and inefficient to drive. 
• Stalling and Starting Issues: A complete coil failure can leave you stranded. The engine may not start or could stall unexpectedly while you are driving, potentially at a dangerous time. 

What to do if you suspect a bad ignition coil:

• Drive Minimally: Opens in new tabDrive your vehicle only to the nearest repair facility for diagnosis and repair. 
• Control Your Driving: Opens in new tabBe gentle on the accelerator and avoid sudden or rapid increases in engine RPM. 
• Seek Professional Diagnosis: Opens in new tabHave the vehicle’s trouble codes scanned with an OBD-II system to identify the misfiring cylinder and schedule a repair. 

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

1. Pull Over Safely: As soon as you notice symptoms, find a safe spot to pull over. 
2. Do Not Delay Repairs: Driving with a failing ignition coil can quickly escalate from a minor inconvenience to an expensive repair. 
3. Consult a Mechanic: Have the vehicle inspected by a professional to diagnose the issue and replace the faulty ignition coil promptly.