How Much Does It Cost to Fix a Misfire?
Last Updated on February 5, 2026
Fixing an engine misfire can be inexpensive (for example, replacing worn ignition parts) or expensive if the misfire is caused by internal engine damage or it’s left long enough to damage emissions components. Most repair bills are driven by three things: (1) the diagnostic time, (2) how many cylinders/parts are affected, and (3) how hard the parts are to access on your specific vehicle.
In this guide, we’ll break down what an engine misfire is, the most common causes, and typical repair cost ranges you may see at a shop—plus when a warranty (or insurance) may help.
- Diagnosis Comes First: Misfire codes don’t always identify the failed part, so testing is usually the best way to avoid unnecessary replacements.
- Ignition Fixes Are Common: Spark plugs and ignition coils are frequent culprits—and typically far cheaper than internal engine repairs.
- Don’t Ignore a Flashing Light: A severe misfire can damage the catalytic converter, turning a manageable repair into a very expensive one.
- Insurance Usually Won’t Pay: Misfires are typically wear-and-tear, but warranties (including emissions coverage) may help in specific situations.
- What Is an Engine Misfire?
- Common Misfire Symptoms
- Most Common Causes of an Engine Misfire
- Typical Cost To Fix an Engine Misfire
- Why Misfire Repair Quotes Vary So Much
- Is It Safe To Drive With a Misfire?
- Will Insurance Cover an Engine Misfire?
- How To Lower the Cost and Prevent Repeat Misfires
- Final Word
- FAQs on Misfire Repair Costs
What Is an Engine Misfire?
A misfire happens when one (or more) cylinders doesn’t contribute normal power. For combustion to happen smoothly, each cylinder needs:
- The right amount of fuel
- The right amount of air
- A strong spark at the right time (gas engines)
- Good compression (mechanical sealing inside the engine)
If any of these are off—even intermittently—the cylinder can misfire. That can trigger a check engine light, rough idle, hesitation under acceleration, and reduced fuel economy.
Quick tip: If your check engine light is flashing and the car is shaking or losing power, treat it as urgent—reduce speed and get the vehicle serviced ASAP to help avoid catalytic converter damage.
Common Misfire Symptoms
| Symptom | What It Often Points To |
|---|---|
| Rough idle or shaking at stoplights | Ignition issue (plugs/coils), vacuum leak, fuel delivery issue |
| Hesitation or stumbling under load | Ignition breakdown under load, fuel injector issue, air/fuel imbalance |
| Check engine light (solid) | Stored trouble code that needs diagnosis (may still be drivable, but don’t ignore) |
| Check engine light (flashing) | More severe misfire—higher risk of catalytic converter damage |
| Hard starts | Fuel/air/spark problem, weak ignition, sensor or leak issue |
Important: Many auto parts stores will read the code for free, but a code read is not the same as a true diagnosis. Misfire codes can tell you which cylinder is affected, but not always the exact part that failed.
Most Common Causes of an Engine Misfire
Misfires are usually traced to ignition, fuel delivery, air/vacuum leaks, sensor inputs, or internal engine condition. Here’s how shops typically bucket the causes:
| Category | Examples | Why It Misfires |
|---|---|---|
| Ignition | Worn spark plugs, failing ignition coils, damaged plug wires (older vehicles) | Weak/no spark = incomplete combustion |
| Fuel Delivery | Clogged or failing fuel injector, low fuel pressure, contaminated fuel | Too little/too much fuel = wrong air-fuel mix |
| Air & Vacuum Leaks | Intake manifold gasket leak, cracked hoses, unmetered air | Extra air leans the mix and disrupts combustion |
| Sensors & Controls | Oxygen sensor issues, MAF/MAP issues, wiring/connectors | Bad inputs can cause incorrect fueling/timing |
| Mechanical | Low compression, valve sealing issues, timing problems | Even with spark and fuel, poor compression can prevent combustion |
Typical Cost To Fix an Engine Misfire
Most misfire repairs start with diagnosis: scanning codes, reviewing freeze-frame data, checking misfire counters, inspecting ignition/fuel components, and (when needed) running tests like a smoke test (vacuum leaks) or compression test (engine health).
Below are typical national estimate ranges you may see for common misfire-related services. Your final price depends on your vehicle, your local labor rate, and whether multiple parts are needed.
| Repair / Test | Typical Total Cost Range | When It’s Common |
|---|---|---|
| General Diagnosis / Check Engine Light Testing | $122–$233 | First step before replacing parts |
| Spark Plug Replacement | $264–$390 | Plugs are due by mileage/condition; misfire under load |
| Ignition Coil Replacement | $225–$331 | Single-cylinder misfire; coil fails under heat/load |
| Fuel Injector Replacement | $763–$966 | Persistent misfire on one cylinder; injector balance issues |
| Intake Manifold Gasket Replacement | $661–$808 | Lean codes + misfire; unmetered air/vacuum leak |
| Oxygen Sensor Replacement | $427–$532 | Fueling corrections are off; emissions-related codes |
| PCV Valve Replacement | $111–$155 | Vacuum/idle issues on some engines (vehicle-dependent) |
| Catalytic Converter Replacement (If Damaged) | $2,177–$2,506 | Misfire ignored long enough to overheat/damage the converter |
| Engine Compression Test | $209–$307 | Rule-out step when misfire suggests low compression |
If your misfire is caused by internal engine damage (low compression, valve sealing problems, timing issues), repairs can move into multi-thousand-dollar territory because of the labor involved. In those cases, a shop’s testing is crucial before you approve major work.
If you want deeper context on plug pricing specifically, see our guide to spark plug replacement costs.
Quick tip: Ask whether the diagnostic fee will be applied to the repair if you approve the work. Many shops will credit some (or all) of the diagnosis time toward the final invoice.
Why Misfire Repair Quotes Vary So Much
- How many cylinders are affected: One bad coil is very different from a random/multiple-cylinder misfire.
- Engine layout and access: Some V6/V8 engines require removing an intake plenum to reach rear spark plugs or coils.
- Root cause vs. symptom: A misfire code can be caused by fuel, air, spark, or compression—guessing can get expensive fast.
- Collateral damage risk: Severe misfires can overheat and damage emissions components, especially the catalytic converter.
- Shop type and local rates: Dealer labor is often higher than in independent shops, and rates vary by region.
Is It Safe To Drive With a Misfire?
It depends on severity. A mild, occasional misfire may feel like a small hesitation—but it can still get worse or damage components over time. A flashing check engine light is a bigger deal: it commonly signals a severe misfire and a higher risk of damaging the catalytic converter if you keep driving.
If the car is shaking heavily, stalling, or the check engine light is flashing, it’s smart to limit driving and get it inspected as soon as you can.
Will Insurance Cover an Engine Misfire?
In most cases, no—a misfire is usually caused by wear, maintenance, or an internal mechanical failure, which standard auto insurance doesn’t cover. However, insurance may apply if the misfire is the direct result of a covered claim (for example, an accident or another covered peril that damaged engine components).
Where you’re more likely to find help is through a manufacturer warranty, an emissions warranty, or an optional product like mechanical breakdown coverage (availability and terms vary by insurer and state). Always check your policy, warranty booklet, and exclusions.
How To Lower the Cost and Prevent Repeat Misfires
- Start with diagnosis, not parts: A code read is helpful, but proper testing prevents “parts darts.”
- Handle it early: The longer a severe misfire is ignored, the higher the risk of damaging the catalytic converter.
- Match the repair to the mileage: If you’re due for plugs by the maintenance schedule, it may be cost-effective to replace them while you’re addressing the misfire.
- Get the estimate in writing: Ask for the test results that support the recommendation (for example, misfire counters, leak test results, injector balance data).
- Ask about parts quality and warranty: OEM vs. aftermarket can matter for ignition and emissions components.
Final Word
Misfires are common, but the cost to fix them depends entirely on the root cause. Budget for diagnosis first, then use the test results to decide whether you’re looking at a straightforward ignition/fuel repair—or something more involved.
And if your check engine light is flashing or the car is running rough, don’t put it off. Addressing a misfire early can help prevent more expensive downstream damage.
