Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car's engine is like a band, and each cylinder is a musician. Cylinder 2 is not playing its part right, causing the engine to run rough.
The engine control module (ECM) has detected that cylinder 2 is not firing properly.
The P0302 code indicates that the engine's second cylinder is experiencing misfires. This means that the combustion process in that cylinder is not happening as it should, which can lead to a rough running engine, increased emissions, and reduced fuel efficiency.
• Check Engine Light is on
• Rough engine idle
• Poor fuel economy
• Loss of engine power
• Engine hesitation
• Faulty spark plug in cylinder 2
• Faulty ignition coil in cylinder 2
• Fuel injector malfunction in cylinder 2
• Vacuum leak near cylinder 2
• Low compression in cylinder 2
OBD-II: On-Board Diagnostics, a system for self-diagnosing and reporting vehicle issues.
ECM: Engine Control Module, the computer that controls engine functions.
Misfire: Failure of the air/fuel mixture in a cylinder to ignite properly.
• Use an OBD-II scanner to confirm the P0302 code
• Inspect the spark plug in cylinder 2 for wear or damage
• Check the ignition coil for proper operation
• Test the fuel injector for cylinder 2
• Perform a compression test on cylinder 2
• Replace the spark plug in cylinder 2
• Replace or repair the ignition coil for cylinder 2
• Clean or replace the fuel injector for cylinder 2
• Repair any vacuum leaks near cylinder 2
• Address any compression issues in cylinder 2
• OBD-II scanner
• Spark plug socket and wrench
• Multimeter
• Compression tester
• Fuel injector tester
$100 - $500
Moderate
• Honda Accord
• Toyota Camry
• Ford F-150
• Regularly replace spark plugs
• Perform routine engine maintenance
• Use quality fuel
Engine Performance
• Do not ignore the Check Engine Light
• Address misfire issues promptly to avoid further damage
Repairs may be covered under the vehicle's powertrain warranty if applicable.
Misfire codes like P0302 have been common since the introduction of OBD-II systems, often related to ignition and fuel system issues.
Moderate – Misfires should be addressed soon to prevent damage to the catalytic converter.
Driving with a misfire can increase emissions and may be illegal in areas with strict emission laws.
• Engine at operating temperature
• Vehicle in idle or under load
Cylinder 2 is located in the engine block, typically the second cylinder in the firing order.
Q: Can I drive my car with a P0302 code?
A: It's not recommended to drive for long periods with a misfire, as it can damage the catalytic converter.
Q: Will a P0302 code cause my car to fail emissions testing?
A: Yes, a misfire can increase emissions and cause your car to fail an emissions test.
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Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.