P0301: Cylinder 1 Misfire Detected

What P0301 usually means

P0301 is a cylinder-specific misfire code. Unlike P0300, it gives you a narrower starting point: the control module sees the misfire pattern tied primarily to cylinder 1.

Start here before chasing parts

• Scan first: save freeze-frame and pending codes before clearing anything.
• Confirm the complaint: compare the stored code with current drivability symptoms.
• Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
• Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.

Suggested workflow

1. Inspect the cylinder 1 spark plug for fouling, gap, or oil contamination.
2. Swap the coil with another cylinder if the design allows and see whether the misfire follows.
3. Check injector pulse and listen for injector operation before replacing it.
4. Confirm compression if ignition and fuel checks do not explain the fault.

Common mistakes

• Assuming every cylinder-specific misfire is a bad coil without checking the plug and connector.
• Skipping compression testing after ignition checks come back clean.

Practical fix guidance

• Repair the failed ignition, fuel, air, or mechanical cause affecting cylinder 1.
• Re-test under the same load or temperature that triggered the original misfire.

Affected brands in this MVP

• Honda

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.