P0304 indicates a misfire in cylinder 4 on your 2013 Dodge Dart. In simple terms, cylinder 4 is not firing properly, which can cause rough idle, reduced power, and potential damage to the catalytic converter if ignored.
What P0304 means
The code P0304 is a generic OBD-II diagnostic trouble code describing a misfire in cylinder 4. A misfire happens when the air-fuel mixture in a cylinder fails to ignite, leading to incomplete combustion and engine performance issues.
Common causes of P0304 on a 2013 Dodge Dart
Misfires can stem from ignition problems, fuel delivery faults, mechanical issues, or vacuum leaks. Here are the most frequent culprits you should check first:
- Faulty spark plug in cylinder 4
- Bad ignition coil or coil-on-plug on cylinder 4
- Clogged or leaking fuel injector for cylinder 4
- Vacuum leak near cylinder 4 or intake manifold gasket issue
- Low fuel pressure or dirty/inconsistent fuel delivery
- Low compression in cylinder 4 due to worn piston rings, valve seat, or head gasket issue
- PCM/ECU fault or incorrect sensor data causing misfire diagnosis
Diagnosing P0304 typically begins with inspecting the ignition system and fuel delivery for cylinder 4, followed by compression testing and leak checks.
How to diagnose P0304 in a 2013 Dodge Dart
Use a systematic approach to confirm the misfire and identify the root cause. The steps assume you have basic tools and an OBD-II scanner capable of live data.
- Connect an OBD-II scanner to confirm the P0304 code and check for related codes (such as P0300 for random misfire).
- Review live data for cylinder 4 misfire counts, ignition coil status, spark plug health, and fuel trims.
- Inspect the spark plug on cylinder 4: look for wear, fouling, oil on the plug, or carbon buildup; replace if necessary.
- Inspect the ignition coil/coil-on-plug for cylinder 4; swap it with another cylinder to see if the misfire follows the coil.
- Check the fuel injector for cylinder 4: listen for operation, measure resistance, and consider swapping injectors to rule out a clogged injector.
- Inspect for vacuum leaks around cylinder 4 and the intake ports; use smoke testing if available.
- Perform a compression test on cylinder 4 and compare with the other cylinders to assess mechanical issues.
- Check for exhaust-related issues that could cause misfire symptoms, such as a clogged catalytic converter or exhaust leak that affects back pressure.
Results from these steps will guide you toward the proper fix, whether it is a simple plug or coil replacement or more involved mechanical repair.
Prioritized fixes for P0304 on a 2013 Dodge Dart
When addressing a P0304, start with the low-cost, high-probability fixes and proceed to more involved repairs if needed.
- Replace the spark plug in cylinder 4 if it shows wear, fouling, or has not been replaced at maintenance intervals.
- Test or replace the ignition coil or coil-on-plug on cylinder 4 if misfire follows the coil in a swap test.
- Inspect/clean or replace the fuel injector for cylinder 4 if you suspect a clog or irregular spray pattern.
- Repair any vacuum leaks around the intake manifold or cylinder 4 area to restore proper air/fuel mixture.
- Check and restore proper fuel pressure; replace any failing fuel pump or regulator components if needed.
- If compression is low in cylinder 4, conduct a more thorough mechanical assessment and repair (valve/seat, piston rings, head gasket).
After performing fixes, clear the codes and take the vehicle for a test drive to confirm that the misfire is resolved and that no new codes appear.
Summary
P0304 is the diagnostic trouble code for a cylinder 4 misfire on a 2013 Dodge Dart. It signals that one cylinder is not firing correctly, causing rough running, power loss, and potential catalyst damage if ignored. Typical causes include ignition issues (spark plug or coil), fuel delivery problems (injector), mechanical issues (low compression), or vacuum leaks. A methodical diagnosis—starting with ignition and fuel components, then moving to compression and leaks—will guide the proper repair, which can range from a spark plug replacement to more extensive mechanical work. Regular maintenance and prompt attention to engine misfires help prevent further damage.