MasterTuning Fault code dictionary (DTC)

P0304 — Cylinder 4 Misfire Detected

Severity: Serious Can you drive? With caution: limp mode possible, have it checked soon Make: All makes (OBD-II standard)
MeaningThe engine control unit has detected irregular combustion or a complete lack of firing in cylinder number four. This means that the air and fuel mixture in that specific cylinder is not burning properly, causing the engine to run rough.
FamilyPowertrain (P)

Typical symptoms

The engine feels shaky or vibrates noticeably at idle
The car hesitates or jerks when you press the gas pedal
The check engine light is flashing or stays on solid
Noticeable drop in engine power

Common causes

Worn out or fouled spark plug in cylinder four
Defective ignition coil pack or plug wire
Fuel injector malfunction supplying cylinder four
Low compression or internal mechanical engine issue

What to do

You should have this checked soon, especially if the check engine light is flashing, because unburned fuel can damage the exhaust catalyst. Ask your mechanic to start by inspecting the spark plug and ignition coil on cylinder four.

Frequently asked questions

What does code P0304 mean?

Cylinder 4 Misfire Detected. The engine control unit has detected irregular combustion or a complete lack of firing in cylinder number four. This means that the air and fuel mixture in that specific cylinder is not burning properly, causing the engine to run rough.

Can I keep driving with code P0304 active?

With caution: limp mode possible, have it checked soon

Common causes — P0304

Worn out or fouled spark plug in cylinder four Defective ignition coil pack or plug wire Fuel injector malfunction supplying cylinder four Low compression or internal mechanical engine issue

How do you fix code P0304?

You should have this checked soon, especially if the check engine light is flashing, because unburned fuel can damage the exhaust catalyst. Ask your mechanic to start by inspecting the spark plug and ignition coil on cylinder four.

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