2008 Mazda P0303: What It Means & Is It Safe to Drive?
P0303 on the 2008 Mazda: 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 2008 Mazda
- 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 2008 Mazda, repairs for P0303 typically fall between $150 and $900, depending on the root cause and labor rates in your area.
Known issues on Mazda
SKYACTIV-G P0303 often appears under light-load driving when injector fouling is the cause. Using top-tier fuel for several tanks sometimes reduces frequency before professional cleaning is needed. Confirm with an injector contribution test.
Most commonly affected models
Mazda3 SKYACTIV-G 2012–2018CX-5 2013–2018Mazda6 2014–2018