P0302 Cylinder 2 Misfire Repair Cost Guide

By Curtis Castiglione

If your check engine light has recently illuminated and a scan tool reveals the code P0302, your vehicle’s computer has detected a misfire in the second cylinder. For many drivers, the immediate concern is the financial impact. How much does a P0302 repair cost? Because this code is a symptom of a problem rather than a specific part failure, the price to fix it can vary significantly. You might spend as little as $150 for a basic spark plug replacement or over $1,500 if the issue involves internal engine damage. On average, most drivers will spend between $200 and $600 to resolve the most common causes of a P0302 code.

It is important to understand that repair prices vary significantly based on your geographic location, your vehicle’s year, make, and model, the type of engine you have, the parts selected, local labor rates, taxes, and shop fees. No single price is universally applicable to every car.

What Is a P0302 Repair?

A P0302 repair is the process of identifying and fixing the reason why cylinder number two is failing to contribute power to the engine. An internal combustion engine requires three main elements to fire correctly: spark, fuel, and compression. If any of these are missing or timed incorrectly in the second cylinder, the engine will misfire, causing the vehicle to shake, lose power, or consume more fuel.

Common components involved in a P0302 repair include:

• Spark Plug: The component that provides the electrical arc to ignite the fuel.
• Ignition Coil: The component that delivers high-voltage electricity to the spark plug.
• Fuel Injector: The nozzle that sprays fuel into the cylinder.
• Wiring Harness: The electrical paths connecting these components to the vehicle's computer.

In more complex cases, the issue may involve a vacuum leak near that specific cylinder or a mechanical failure such as a burnt valve, a worn piston ring, or a leaking head gasket. Because of this, the 'repair' is not a single service but rather a targeted fix based on professional diagnosis.

Average P0302 Repair Cost

The total P0302 repair cost is typically divided into two phases: the diagnostic fee and the actual repair. You should expect to pay a diagnostic fee of $100 to $150 upfront. This covers the technician's time to use specialized equipment, such as scanners and oscilloscopes, to verify the cause of the misfire.

Once the cause is identified, here is a look at how much a P0302 repair costs based on the most common fixes (prices include the initial diagnosis):

Parts Cost

The price of parts varies by vehicle type and the quality of the components used. A single spark plug for a standard domestic sedan may cost $10 to $20. However, high-performance iridium or platinum plugs can cost more. An ignition coil can range from $60 to $180 depending on whether you use original equipment manufacturer (OEM) parts or aftermarket alternatives.

If the issue is a fuel injector, the part alone can cost between $100 and $300. In cases involving mechanical failure, parts like head gaskets or valves can cost hundreds of dollars, though labor becomes the primary expense in those scenarios.

Labor Cost

P0302 labor costs are a major factor in the final bill. Most independent shops charge between $100 and $150 per hour, while dealerships often charge $180 to $250 per hour.

For a simple ignition coil or spark plug replacement on a four-cylinder engine, the labor time is usually less than one hour. However, on some V6 or V8 engines, the intake manifold may need to be removed to access the cylinder two spark plug or coil. This can increase labor time to three or four hours, significantly raising the total P0302 replacement cost.

What Can Make the Repair More Expensive?

Several factors can drive up the P0302 price:

1. Engine Design: If your engine is a 'transverse' V6 (mounted sideways), cylinder two may be located under a heavy intake plenum. This requires extra hours of labor just to reach the spark plugs.
2. Root Cause: If the misfire is caused by low compression due to a mechanical fault, you are looking at an engine teardown. This can cost thousands of dollars, making you ask, 'is this repair worth it?' on an older, high-mileage vehicle.
3. Vehicle Make: High-end luxury brands generally have more expensive parts and require specialized diagnostic software, which increases the shop's overhead and your final price.

Dealership vs. Independent Repair Shop

Where you take your vehicle will change the final bill.

• Dealerships: They use OEM parts and technicians specifically trained for your brand. They offer specialized knowledge but usually have the highest labor rates and part markups.
• Independent Shops: These shops often offer more competitive pricing and can use high-quality aftermarket parts to save you money. They are excellent for common repairs like spark plugs and coils.
• Specialty Shops: An electrical or engine specialist might be necessary if the misfire is caused by a deep-seated wiring issue or a complex computer fault that a general shop cannot find.
• DIY Repair: For those with mechanical skills, replacing a spark plug or coil yourself is the cheapest option, often costing under $100. However, you risk 'parts cannoning'—replacing parts you don't need because you skipped the professional diagnosis.

Can I Drive With This Problem?

A common question is, 'can I drive with a P0302 code?' The short answer is no, you should not drive more than necessary.

Driving with a consistent misfire allows unburned fuel to enter your exhaust system. This fuel will ignite inside the catalytic converter, causing it to overheat and melt the internal honeycomb structure. Replacing a catalytic converter can cost between $1,000 and $2,500, turning a relatively cheap fix into a financial disaster.

Warning: If your check engine light is flashing, the misfire is severe enough to cause immediate damage. In this case, the vehicle should be towed to a shop. If the light is steady, you may be able to drive it a short distance to a mechanic, but avoid high speeds and heavy acceleration.

How to Avoid Paying for Unnecessary Repairs

The best way to avoid unnecessary costs is to insist on a proper diagnosis rather than just 'throwing parts' at the problem.

A professional technician will often perform a 'swap test.' For example, they will move the ignition coil from cylinder two to cylinder one. If the code changes to P0301 (misfire on cylinder one), they have definitive proof the coil is bad. If the misfire remains on cylinder two, they know the coil is fine and the problem lies elsewhere, such as the fuel injector or a compression issue. This prevents you from paying for a part that doesn't actually fix the problem.

Questions to Ask the Repair Shop

Before you authorize the work, ask your service writer the following questions:

1. Did the diagnostic test confirm that the misfire follows a specific component like a coil or plug?
2. Did you perform a compression test on cylinder two to rule out internal engine damage?
3. Is the quote for an OEM part or an aftermarket part?
4. Are there any other maintenance items, like a valve cover gasket, that should be replaced while the engine is already apart?
5. Does the repair come with a parts and labor warranty?

Bottom Line

While a P0302 code can be stressful, it is often a straightforward fix involving a spark plug or ignition coil. The key to keeping your costs low is acting quickly to avoid damaging your catalytic converter and ensuring the shop performs a logical diagnostic process. By understanding that the how much does P0302 repair cost question is answered by a combination of professional testing and specific parts replacement, you can make an informed decision that keeps your vehicle running smoothly without overpaying for unnecessary repairs.