2015 Pontiac P0304: What It Means & Is It Safe to Drive?
P0304 on the 2015 Pontiac: Cylinder 4 Misfire Detected. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
What this code means
Misfire confirmed on cylinder 4. On 4-cylinder engines, this is the last cylinder—check coil and plug first, then injector, then compression.
Common causes on the 2015 Pontiac
- Worn spark plug on cylinder 4
- Failed ignition coil on cylinder 4
- Faulty or clogged fuel injector
- Low compression or valve issue
Symptoms
- Check Engine Light
- Rough idle and shaking
- Poor acceleration or power loss
Typical fixes
- Replace spark plug and COP coil on cylinder 4
- Clean or replace fuel injector
- Compression and leak-down test if basic parts check out
Repair cost range
For a 2015 Pontiac, repairs for P0304 typically fall between $150 and $900, depending on the root cause and labor rates in your area.
Known issues on Pontiac
Pontiac Ecotec 2.4L P0304 on cylinder 4 is a known timing chain stretch symptom on this engine. Listen for a rattle at cold startup—if present, the timing chain is the root cause rather than a coil or plug failure. The 2.4L Ecotec timing chain stretch is a widely documented issue.
Most commonly affected models