Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer noticed that the first cylinder in the engine isn't working right. It's like one of the parts of a machine isn't moving the way it should.
The engine's computer has detected that the first cylinder is not firing properly. This means the fuel in that cylinder isn't burning as it should, which can affect engine performance.
The P0301 code indicates that the engine control module (ECM) has detected a misfire in cylinder number 1. A misfire occurs when the air-fuel mixture in the cylinder does not ignite properly, which can be due to a variety of reasons such as lack of spark, poor fuel delivery, or mechanical issues.
• Check Engine Light is on
• Rough engine idle
• Poor fuel economy
• Engine hesitation or jerking
• Loss of power
• Faulty spark plug in cylinder 1
• Faulty ignition coil
• Fuel injector issue in cylinder 1
• Vacuum leak near cylinder 1
• Low engine compression
ECM: Engine Control Module, the computer that controls the engine.
Misfire: When the air-fuel mixture in a cylinder does not ignite properly.
• Use an OBD-II scanner to confirm the P0301 code.
• Inspect the spark plug in cylinder 1 for wear or damage.
• Check the ignition coil for proper operation.
• Test the fuel injector for cylinder 1.
• Perform a compression test on cylinder 1.
• Replace the spark plug in cylinder 1.
• Replace or repair the ignition coil.
• Clean or replace the fuel injector.
• Fix any vacuum leaks.
• Repair engine mechanical issues if present.
• OBD-II scanner
• Spark plug socket and wrench
• Compression tester
• Multimeter
• Fuel injector tester
$100 - $500
Moderate
• Honda Accord
• Toyota Camry
• Ford F-150
• Regularly replace spark plugs and ignition components.
• Perform routine engine maintenance.
• Use high-quality fuel.
Engine Performance
• Avoid driving the vehicle if the engine is misfiring.
• Get the vehicle inspected by a professional mechanic.
Check with your vehicle manufacturer for warranty coverage on ignition and engine components.
P0301 has been a common diagnostic trouble code since OBD-II systems were introduced, often related to ignition system issues.
High – Misfires can lead to engine damage if not addressed promptly.
Driving with a misfire can cause damage to the catalytic converter and increase emissions.
• Engine at normal operating temperature
• Vehicle in idle or under load
Cylinder 1 is typically located at the front of the engine on inline engines or on one side in V-type engines.
Q: Can I drive with a P0301 code?
A: It's not recommended to drive with a misfire, as it can cause further engine damage.
Q: How serious is a cylinder misfire?
A: A misfire is serious as it can lead to poor engine performance and potential damage to the catalytic converter.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
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Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal 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.