P0307

High Severity

Cylinder 7 Misfire Detected

Ignition System

What Does P0307 Mean?

Cylinder 7 is misfiring. Only on V8 engines.

Common Fix

Replace spark plug or coil

Estimated Cost (DIY)

$20 - $500

Symptoms

  • ⚠️Rough idle
  • ⚠️Power loss
  • ⚠️Check engine light

Common Causes

Bad spark pluglikely
Faulty coillikely
Bad injectorpossible

How to Diagnose P0307

  1. 1Swap plug/coil
  2. 2Check injector
  3. 3Compression test

OEM Diagnostic Flowchart

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Related Resources

Repair guides, symptom pages, and wiring diagrams related to P0307.

Frequently Asked Questions

What V8 engines have cylinder 7 issues?
GM V8s with AFM/DFM (cylinder deactivation) sometimes have specific cylinder issues. Check for AFM-related problems.
Is P0307 an emergency?
If the check engine light flashes, yes — pull over. Steady light means you can drive to a shop.

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