How much does it cost to fix P0302?

DIY repair typically costs $15–$250 for parts. Professional repair runs $100–$2500 including parts and labor.

P0302

Powertrain

Moderate

Cylinder 2 Misfire Detected

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The P0302 trouble code indicates that your vehicle's powertrain control module (PCM) has detected a misfire specifically in cylinder 2 of your engine. A misfire occurs when the air-fuel mixture in a cylinder fails to ignite properly or at the right time, disrupting the smooth operation of your engine. The PCM continuously monitors engine performance through crankshaft position sensors, and when it detects irregular rotation patterns indicating incomplete combustion in cylinder 2, it triggers this code and illuminates the Check Engine Light. This is one of the most common diagnostic trouble codes and can affect any vehicle with a multi-cylinder engine, regardless of make or model.

While a single-cylinder misfire like P0302 is generally less severe than a random multiple-cylinder misfire (P0300), it still requires prompt attention to prevent further damage. Driving with a persistent misfire can damage your catalytic converter due to unburned fuel entering the exhaust system, where it can overheat and destroy the expensive catalyst material. Additionally, misfires reduce fuel efficiency, increase emissions, and can cause damage to other engine components over time. The good news is that most causes of P0302 are relatively straightforward to diagnose and repair, with common culprits being spark plugs, ignition coils, and fuel injectors.

If you're experiencing symptoms of a cylinder 2 misfire, it's recommended to address the issue within a week to avoid catalytic converter damage and worsening drivability problems. Many repairs, such as replacing spark plugs or ignition coils, are DIY-friendly for moderately skilled home mechanics with basic tools. However, if the misfire is caused by internal engine problems like low compression due to worn valves or piston rings, professional diagnosis and repair will be necessary. Starting with the simplest and most common fixes—inspecting and replacing the spark plug and ignition coil for cylinder 2—often resolves the problem quickly and affordably.

Severity

Moderate — Address SoonThis Week

Symptoms

•Check Engine Light illuminated
•Rough idle or engine vibration
•Loss of power or hesitation during acceleration
•Poor fuel economy
•Engine running roughly or stumbling
•Strong smell of unburned fuel from exhaust

Likely Causes

Faulty or worn spark plug in cylinder 235%

Spark plugs wear over time and can fail to ignite the air-fuel mixture properly. This is the most common cause of single-cylinder misfires and is relatively inexpensive to fix.

Defective ignition coil or coil pack for cylinder 230%

The ignition coil provides high voltage to the spark plug. When it fails, the spark plug won't receive adequate energy to create a strong spark, resulting in misfires.

Fuel injector clogged or malfunctioning in cylinder 215%

A clogged or faulty fuel injector prevents the proper amount of fuel from reaching cylinder 2, causing a lean condition and subsequent misfire during combustion.

Low compression in cylinder 2 due to worn piston rings, valves, or head gasket12%

Mechanical wear or damage can reduce compression, preventing proper combustion. This is more serious and expensive to repair than ignition or fuel system issues.

Vacuum leak affecting cylinder 2 or damaged spark plug wire8%

Air leaks in the intake manifold or cracked spark plug wires can disrupt the air-fuel ratio or spark delivery, leading to misfires in individual cylinders.