P0304 Ford F-150
Cylinder 4 Misfire Detected · Powertrain Code · High · Repair: Moderate
What is P0304?
Misfire detected in cylinder 4. Typically caused by a worn spark plug, bad ignition coil, faulty fuel injector, or low compression in that cylinder.
When the Ford F-150 triggers code P0304 (cylinder 4 misfire detected), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the Ford F-150.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Ford F-150.
Common Causes on Ford F-150
- Failed coil-on-plug on cylinder 4
- Worn or incorrect gap spark plug on cylinder 4
- Carbon buildup on intake valve (EcoBoost)
- Fuel injector failure or clogging on cylinder 4
Symptoms
- Check engine light (may flash)
- Rough idle with rhythmic miss
- Engine shaking at idle
- Reduced power
- Catalytic converter overheating from unburned fuel if ignored
Notes for Ford F-150
On the 2.7L EcoBoost V6, cylinder 4 is on the rear bank and harder to access — budget extra time for coil and plug replacement.