A worn or fouled spark plug or failed ignition coil on the affected cylinder, causing repeated misfires that trigger fuel cutoff.; A clogged, stuck-closed, or electrically failed fuel injector that creates a lean misfire on that cylinder.; Low fuel pressure or a restricted fuel filter that leans out one or more cylinders under load.; A vacuum leak at the intake manifold gasket or a cracked intake runner affecting a single cylinder.; Mechanical faults such as a burned valve, worn cam lobe, or broken valve spring that prevent proper combustion.; A faulty crankshaft position sensor or reluctor wheel that causes the computer to misidentify misfire events.; Wiring damage or a poor connection at the ignition coil or injector harness for the affected cylinder.

DTC codes / P03xx · Ignition system and misfire / P0363

P0363Misfire Detected - Fueling Disabled

Q: What does code P0363 mean?

Misfire Detected - Fueling Disabled. P0363 means the engine computer has detected a misfire severe enough that it has deliberately shut off fuel delivery to the affected cylinder to protect the catalytic converter from raw fuel. The code is stored after the misfire monitor counts enough misfire events and the powertrain control module commands the fuel injector for that cylinder to stop firing.

P0363 means the engine computer has detected a misfire severe enough that it has deliberately shut off fuel delivery to the affected cylinder to protect the catalytic converter from raw fuel. The code is stored after the misfire monitor counts enough misfire events and the powertrain control module commands the fuel injector for that cylinder to stop firing.

SystemPowertrain

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaIgnition system and misfire

Symptoms you may notice

The check engine light is illuminated, often flashing while the misfire is actively occurring.
The engine may run rough, shake, or feel down on power because one cylinder is no longer receiving fuel.
A noticeable fuel smell may come from the exhaust if unburned fuel reached the converter before fueling was cut.
The vehicle may enter limp mode or limit engine speed to prevent converter damage.
Often no symptoms besides the warning light once the computer has disabled fueling and the engine smooths out slightly.

Common causes, most likely first

A worn or fouled spark plug or failed ignition coil on the affected cylinder, causing repeated misfires that trigger fuel cutoff.
A clogged, stuck-closed, or electrically failed fuel injector that creates a lean misfire on that cylinder.
Low fuel pressure or a restricted fuel filter that leans out one or more cylinders under load.
A vacuum leak at the intake manifold gasket or a cracked intake runner affecting a single cylinder.
Mechanical faults such as a burned valve, worn cam lobe, or broken valve spring that prevent proper combustion.
A faulty crankshaft position sensor or reluctor wheel that causes the computer to misidentify misfire events.
Wiring damage or a poor connection at the ignition coil or injector harness for the affected cylinder.

How to diagnose and fix it

Scan all stored and pending codes, then record freeze-frame data to identify which cylinder or cylinders are affected and under what conditions the misfire occurs.
Perform a visual inspection of the ignition coils, spark plugs, and injector connectors on the affected cylinder for damage, corrosion, or looseness.
Swap the ignition coil and spark plug from the misfiring cylinder to a known-good cylinder and recheck misfire counts to see if the fault follows the component.
Measure fuel pressure and check injector pulse width with a scan tool or oscilloscope to confirm the injector is being commanded and delivering fuel.
Run a relative compression test or cylinder leak-down test to rule out mechanical valve or piston problems on the affected cylinder.
Inspect the intake manifold and vacuum lines for leaks near the affected cylinder using propane or smoke testing.
Repair the confirmed root cause, clear the codes, and verify with a road test that misfire counters stay at zero and P0363 does not return.

Why fueling was disabled and what it hides

P0363 is a consequence code, not the root cause; the computer disables fueling after detecting a misfire, so diagnosing the original misfire is the real repair.
A flashing check engine light with P0363 means the converter is at risk, and continuing to drive can melt the substrate even after fueling is cut on one cylinder.
Technicians sometimes replace the injector on the dead cylinder when the real fault is a bad ignition coil that caused the misfire and subsequent fuel cutoff.
The misfire monitor can be fooled by a failing crankshaft position sensor or a damaged reluctor wheel, setting P0363 without any true combustion problem.
After repairs, the fuel injector for the disabled cylinder may need a scan-tool relearn or several drive cycles before the computer restores normal fueling.

Can I keep driving with P0363?

Do not continue driving with P0363 active, especially if the check engine light is flashing, because raw fuel can overheat and destroy the catalytic converter. Have the vehicle towed or driven only a very short distance to a repair shop, and avoid heavy acceleration or highway speeds until the misfire is fixed.

Tools that help

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