P0303 Ford Explorer
Cylinder 3 Misfire Detected · Powertrain Code · High · Repair: Moderate
What is P0303?
Misfire detected in cylinder 3. Typically caused by a worn spark plug, bad ignition coil, faulty fuel injector, or low compression in that cylinder.
When the Ford Explorer triggers code P0303 (cylinder 3 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 Explorer.
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 Explorer.
Common Causes on Ford Explorer
- Failed coil-on-plug ignition coil on cylinder 3
- Worn or fouled spark plug on cylinder 3
- Intake valve carbon deposits (EcoBoost direct injection)
- Low compression on cylinder 3 from valve or piston ring issue
Symptoms
- Check engine light (flashing if active misfire)
- Rough idle
- Vibration felt through steering wheel
- Reduced power under acceleration
- Increased exhaust emissions
Notes for Ford Explorer
On EcoBoost engines, if multiple cylinders start misfiring at 60k+ miles, carbon buildup on intake valves is likely — a walnut blast service resolves it.