2005 Ford P0303: What It Means & Is It Safe to Drive?
P0303 on the 2005 Ford: Cylinder 3 Misfire Detected. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
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What this code means
The PCM has detected a misfire specifically on cylinder 3. Diagnosis follows the same steps as P0301—swap parts to the same position on a known-good cylinder to isolate the fault.
Common causes on the 2005 Ford
- Worn or fouled spark plug on cylinder 3
- Failing ignition coil on cylinder 3
- Leaking or clogged fuel injector
- Low compression on cylinder 3
Symptoms
- Check Engine Light, often flashing under load
- Rough idle or shaking
- Loss of power, hesitation
Typical fixes
- Replace spark plug and coil on cylinder 3
- Test and replace fuel injector
- Compression test if ignition parts don't resolve it
Repair cost range
For a 2005 Ford, repairs for P0303 typically fall between $150 and $900, depending on the root cause and labor rates in your area.
Known issues on Ford
Ford 5.4L P0303 often involves a blown-out spark plug on cylinder 3. Inspect the spark plug threads in the head before assuming a coil failure. On 4.6L V8 Explorers, cylinder 3 is on the driver-side bank and COP failure is the most common cause.
Most commonly affected models
F-150 5.4L 3V 2004–2010Explorer 4.6L 2002–2005Mustang GT 4.6L 2005–2009