P0300 on Ford: Random or Multiple Cylinder Misfire Detected
Severity: 3 of 4
Park it if the check engine light is flashing or the engine is shaking. A flashing light means misfires severe enough to damage the catalytic converter and in extreme cases cause an exhaust fire. If the light is steady and the misfire is mild, drive only as far as needed to get it diagnosed, gently and without heavy loads.
Estimate range covers the repairs listed below; see the cost breakdown. A flashing check engine light, a hot temperature gauge, or brakes that feel different mean stop driving and get help.
What P0300 usually means on a Ford
Ford service bulletins for 2011 to 2014 F-150 trucks with the 3.5 EcoBoost describe stumble or misfire on hard acceleration after highway driving in humid conditions, caused by moisture collecting in the charge air cooler. The fixes involved air deflector changes and a PCM software update, and the bulletins note P0430 may also appear.
On non turbo Ford engines, spark plugs and coils remain the common causes.
Most likely causes on Ford vehicles
- Worn spark plugs (EcoBoost plugs often need shorter intervals)
- Ignition coils
- Intercooler condensation on affected EcoBoost engines
- Vacuum leaks
Order reflects cost and likelihood in general; your vehicle may differ. Confirm with testing before buying parts.
Ford specific tips
- Note whether misfires happen on hard acceleration in damp weather.
- Check for technical service bulletins.
Estimated repair cost
This is an estimate, built from typical parts price ranges plus labor hours times an assumed shop rate of $110 to $190 per hour. Actual prices vary by vehicle, region, and shop. Diagnosis fees are often extra.
| Repair | Parts | Labor | Estimate (low / high) |
|---|---|---|---|
| Spark plugs, full set | $20 to $120 | 0.5 to 2.5 h | $20 + 0.5 × $110 = $75 $120 + 2.5 × $190 = $595 |
| Vacuum hose or intake gasket | $10 to $120 | 0.5 to 2.5 h | $10 + 0.5 × $110 = $65 $120 + 2.5 × $190 = $595 |
| Ignition coil, one | $30 to $150 | 0.2 to 1.0 h | $30 + 0.2 × $110 = $52 $150 + 1.0 × $190 = $340 |
| Fuel pump | $120 to $600 | 1.5 to 3.5 h | $120 + 1.5 × $110 = $285 $600 + 3.5 × $190 = $1,265 |
Costs are generic for this code; parts and labor on some Ford models may run higher.
Watch a repair video
How to Fix a Random Engine Misfire in Your Car (Code P0300) (Scotty Kilmer). Third-party video, loads from YouTube (privacy-enhanced mode) only when you press play. Procedures vary by vehicle. Search YouTube for “P0300 Ford fix” videos.
Repair manuals
Step-by-step service manuals for Ford with torque specs and wiring diagrams:
Haynes manuals for Ford Chilton manuals
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Check Ford recalls
Enter your VIN at the NHTSA recall lookup before paying for repairs.
FAQ
Do EcoBoost engines need spark plugs more often?
Turbo engines work plugs harder; follow the maintenance schedule closely and consider shorter intervals under heavy use.
Read the full P0300 guide or more Ford check engine notes.