Safety Warning
- Continuing to drive with misfires can damage the catalytic converter
- Rough idle and reduced power can affect vehicle control
- Unburned fuel from misfires is a fire hazard
- Always disconnect battery before working on ignition components
Quick Diagnosis Summary
If your 2019 Nissan Rogue is displaying the P0304 diagnostic trouble code, you're dealing with a cylinder 4 misfire. This OBD-II code specifically indicates that the engine's fourth cylinder is not firing properly, creating an imbalance that affects your vehicle's performance. While this is a common issue in Nissan Rogues, especially those approaching or exceeding 60,000 miles, the good news is that most causes are relatively straightforward to diagnose and repair.
Understanding the P0304 Code in Your Nissan Rogue
The P0304 code is triggered when your vehicle's powertrain control module (PCM) detects that cylinder 4 is not contributing its expected power output. The PCM monitors crankshaft position and can identify when one cylinder isn't firing correctly by detecting irregular rotation patterns. In 2019 Nissan Rogues equipped with the 2.5L QR25DE engine, this misfire detection system is highly sensitive and will typically trigger the check engine light after just a few misfire events.
Symptoms of P0304 Cylinder 4 Misfire
When your 2019 Nissan Rogue experiences a cylinder 4 misfire, you'll likely notice several distinct symptoms:
- Rough idle: The engine will feel shaky or unstable when stopped at traffic lights or in park
- Reduced power: Acceleration will feel sluggish, especially during highway merging or climbing hills
- Engine hesitation: The vehicle may stumble or hesitate during acceleration
- Check engine light: This will illuminate and may flash if the misfire is severe
- Poor fuel economy: You may notice decreased gas mileage as the engine works harder to compensate
- Engine knocking: Unusual sounds from the engine bay, particularly during acceleration
- Exhaust odor: A strong fuel smell from the exhaust due to unburned gasoline
Common Causes of P0304 in 2019 Nissan Rogue
Faulty Ignition Coil (High Probability)
Ignition coil failure is the most common cause of P0304 in 2019 Nissan Rogues. These vehicles use individual coil-on-plug ignition coils for each cylinder, and the coil for cylinder 4 is particularly susceptible to failure between 60,000-100,000 miles. When an ignition coil fails, it cannot generate the high voltage needed to create a strong spark, resulting in incomplete combustion or complete misfires.
Worn Spark Plug (High Probability)
Spark plugs in the 2019 Nissan Rogue typically last 60,000-100,000 miles, depending on driving conditions. The spark plug in cylinder 4 may become fouled with carbon deposits, oil, or fuel, or the electrode gap may widen beyond specifications. A worn or fouled spark plug cannot reliably ignite the air-fuel mixture, causing the P0304 code.
Fuel Injector Malfunction (Medium Probability)
The fuel injector responsible for cylinder 4 can become clogged with debris or fail mechanically. This results in improper fuel delivery – either too much (rich condition) or too little (lean condition) – both of which can cause misfires. While less common than ignition-related issues, fuel injector problems become more likely as mileage increases.
Vacuum Leak (Medium Probability)
A vacuum leak affecting cylinder 4's air intake can create an overly lean air-fuel mixture. Common leak points include cracked vacuum hoses, a damaged intake manifold gasket, or loose connections around the throttle body. The 2019 Rogue's plastic intake components can develop cracks over time, especially in extreme temperature conditions.
Low Compression (Low Probability)
Internal engine problems such as worn piston rings, damaged valves, or head gasket issues can reduce compression in cylinder 4. While uncommon in a 2019 vehicle with proper maintenance, these issues can occur due to manufacturing defects, overheating, or severe neglect.
Diagnosing the P0304 Code
Proper diagnosis is crucial for effective repair. Start by using an OBD-II scanner to confirm the P0304 code and check for additional codes that might indicate related problems. Here's a systematic approach:
- Visual inspection: Examine the ignition coil, spark plug wire (if equipped), and surrounding components for obvious damage
- Swap test: Exchange the cylinder 4 ignition coil with another cylinder's coil. If the misfire follows the coil, you've identified the problem
- Spark plug inspection: Remove and examine the cylinder 4 spark plug for wear, fouling, or damage
- Compression test: If ignition components check out, perform a compression test on cylinder 4
- Fuel pressure test: Check fuel pressure and injector operation if other tests are inconclusive
Repair Options for P0304
Professional Repair
A qualified technician can quickly diagnose and repair P0304 issues using specialized diagnostic equipment. Professional repair ensures proper torque specifications, quality parts, and warranty coverage. Most shops will charge 1-2 hours of diagnostic time plus parts and labor for the actual repair.
DIY Repair
The P0304 repair has moderate DIY feasibility for mechanically inclined owners. Replacing spark plugs and ignition coils requires basic tools and can be completed in 30-60 minutes. However, always disconnect the battery before working on ignition components and ensure the engine is cool to prevent burns.
Cost Breakdown for P0304 Repair
Repair costs for P0304 in a 2019 Nissan Rogue typically range from $150-$250, depending on the root cause:
- Spark plug replacement: $80-$150 (parts $30-$60, labor $50-$90)
- Ignition coil replacement: $120-$200 (parts $60-$120, labor $60-$80)
- Fuel injector cleaning: $100-$180 (service $80-$150, additives $20-$30)
- Fuel injector replacement: $200-$350 (parts $120-$200, labor $80-$150)
- Vacuum leak repair: $50-$200 (depending on location and extent of damage)
Prevention Tips
Prevent future P0304 codes and cylinder misfires with these maintenance practices:
- Replace spark plugs according to Nissan's maintenance schedule (typically every 100,000 miles)
- Use quality fuel and consider periodic fuel system cleaning
- Address check engine lights promptly to prevent secondary damage
- Maintain proper engine oil levels and change intervals
- Inspect and replace air filters regularly to prevent debris ingestion
- Have vacuum hoses and intake components inspected during routine maintenance
Frequently Asked Questions
You should address the P0304 code soon but can drive carefully for short distances. Continuing to drive with misfires can damage your catalytic converter, which is much more expensive to replace than the typical causes of this code. If the check engine light is flashing, stop driving immediately as this indicates severe misfires.
The easiest diagnostic method is to swap the cylinder 4 ignition coil with another cylinder's coil. If the misfire code changes to the new cylinder location, the coil is faulty. If P0304 persists, check the spark plug or other cylinder 4-specific components.
Yes, the P0304 code will typically cause your vehicle to fail emissions testing. Most states require all diagnostic trouble codes to be cleared and the vehicle to pass a drive cycle before emissions compliance is verified.
Ignition coils in 2019 Nissan Rogues typically last 60,000-100,000 miles, though some may fail earlier due to heat stress or manufacturing variations. The coil-on-plug design means each cylinder has its own coil, so they often fail individually rather than all at once.
Poor quality fuel or contaminated gas can contribute to misfires, but it would typically affect multiple cylinders rather than just cylinder 4. If you suspect bad fuel, try adding a fuel system cleaner and filling up with high-quality gasoline from a reputable station.
While you can replace just the cylinder 4 spark plug, it's often more cost-effective to replace all spark plugs at once since they wear at similar rates. This prevents having to repeat the labor in the near future when other cylinders develop similar issues.