P0301High SeverityPowertrain

Cylinder 1 Misfire Detected

Fault pattern analysis, verified repair data, and DIY cost breakdown

🔍 Fault Context

P0301 targets a confirmed misfire in cylinder 1. The ECM tracks crankshaft velocity drops and isolates them to specific cylinders using the CKP sensor signal. A cylinder-specific code like P0301 is easier to diagnose than P0300 because it narrows the problem to one combustion event. Historical fault pattern data points to ignition coil failure as the single most common cause on coil-on-plug engines, especially on high-mileage Ford and GM vehicles.

⚠️ Symptom Mapping

  • Engine shake felt most at idle
  • Rough acceleration
  • Check engine light, possibly flashing
  • Specific cylinder power loss

📊 Generative Data Fixes

Ranked by historical repair data aggregates across verified fault reports

1. Failed ignition coil (cylinder 1)40%
2. Fouled or worn spark plug (cylinder 1)30%
3. Leaking or clogged fuel injector (cylinder 1)15%
4. Low compression in cylinder 110%
5. Intake manifold runner control stuck5%

🔧 DIY Difficulty and Tools Required

DIY Difficulty Score

1
2
3
4
5
Beginner (2/5)

Tools Required

OBD2 ScannerSpark plug socketTorque wrenchCompression tester

DIY Cost

$20 - $180

Shop Cost

$150 - $500

Frequently Asked Questions

How do I confirm cylinder 1 location on my engine?

Cylinder 1 is typically the front-most cylinder on inline engines and the front-right on V-engines. Check your service manual for your specific layout.

Should I replace all spark plugs or just cylinder 1?

If the plugs are near their service interval, replace all of them. It saves labor cost and prevents the others from failing shortly after.

Can a bad injector cause P0301?

Yes. A leaking injector floods the cylinder with too much fuel; a clogged injector starves it. Both cause misfires. Use an injector balance test to confirm.

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