Worn or fouled spark plug on cylinder 4; Failed ignition coil or coil-on-plug boot for cylinder 4; Faulty fuel injector for cylinder 4 (clogged, leaking, or electrically open); Vacuum leak at the intake manifold runner or gasket near cylinder 4; Low compression on cylinder 4 due to worn rings, valves, or head gasket; Damaged wiring or connector to the cylinder 4 coil or injector; Mechanical valvetrain issue such as a collapsed lifter or worn cam lobe on cylinder 4

DTC codes / Nissan codes / P1304

P1304 · NissanCylinder 4 Misfire

Q: What does code P1304 mean?

Cylinder 4 Misfire. P1304 on Nissan vehicles means the engine control module (ECM) has detected a misfire specifically on cylinder 4, usually by monitoring crankshaft speed fluctuations that indicate that cylinder is not contributing power evenly. The ECM sets this code when the misfire exceeds a calibrated threshold, often counting misfire events over a specific number of engine cycles.

P1304 on Nissan vehicles means the engine control module (ECM) has detected a misfire specifically on cylinder 4, usually by monitoring crankshaft speed fluctuations that indicate that cylinder is not contributing power evenly. The ECM sets this code when the misfire exceeds a calibrated threshold, often counting misfire events over a specific number of engine cycles.

SystemPowertrain

Code typeNissan specific

SeverityHigh

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Check engine light illuminated, often flashing if the misfire is severe
Noticeable engine shake or vibration at idle, especially when cold
Rough running or hesitation during acceleration
Reduced power and poor fuel economy
Often no symptoms besides the warning light when the misfire is intermittent
Possible rotten egg smell from the exhaust if unburned fuel reaches the catalytic converter

Common causes, most likely first

Worn or fouled spark plug on cylinder 4
Failed ignition coil or coil-on-plug boot for cylinder 4
Faulty fuel injector for cylinder 4 (clogged, leaking, or electrically open)
Vacuum leak at the intake manifold runner or gasket near cylinder 4
Low compression on cylinder 4 due to worn rings, valves, or head gasket
Damaged wiring or connector to the cylinder 4 coil or injector
Mechanical valvetrain issue such as a collapsed lifter or worn cam lobe on cylinder 4

How to diagnose and fix it

Scan all stored and pending codes, then swap the cylinder 4 ignition coil with a known-good coil from another cylinder and see if the misfire moves
Remove and inspect the cylinder 4 spark plug for wear, fouling, or incorrect gap, and replace if needed
Perform a cylinder balance test or use a scan tool to monitor misfire counters per cylinder while disabling injectors one at a time
Check for vacuum leaks around the intake manifold and cylinder 4 runner using a smoke machine or carb cleaner
Measure fuel injector resistance and listen for injector clicking; swap the cylinder 4 injector with another cylinder to see if the misfire follows
Run a compression test and, if low, a cylinder leak-down test on cylinder 4 to rule out mechanical faults
Inspect the wiring harness and connectors at the cylinder 4 coil and injector for chafing, corrosion, or loose pins

What Nissan technicians check before replacing parts

A flashing check engine light with P1304 means the misfire is severe enough to damage the catalytic converter, so stop driving and diagnose immediately rather than clearing the code.
Nissan engines are known for ignition coil failures that often start as an intermittent misfire when hot or under load, so swapping coils between cylinders is the fastest way to confirm the fault.
A vacuum leak at the intake manifold gasket can cause a single-cylinder misfire that mimics a bad injector or coil, so always smoke-test the intake before condemning ignition parts.
On some Nissan models, a dirty or failing mass airflow sensor can skew fuel trims and set a cylinder-specific misfire code even though the root cause is not on that cylinder.
Low compression from a worn valve seat or piston ring on cylinder 4 will set P1304 repeatedly after parts are replaced, so a compression test should be part of the initial diagnosis.

Can I keep driving with P1304?

Do not continue driving if the check engine light is flashing, because raw fuel in the exhaust can quickly overheat and destroy the catalytic converter. If the light is steady and the engine runs smoothly, you can drive cautiously to a repair shop, but avoid hard acceleration and towing.

Tools that help

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Guidance is general and written for Nissan vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.