Engine

P0363 — Misfire Detected - Fueling Disabled

Severity: medium Drive with care, to a shop

What P0363 means

The engine control module monitors crankshaft speed variations to detect misfires in each cylinder. When a cylinder misfires badly enough, the module shuts off that cylinder's injector so unburned fuel does not reach and overheat the catalytic converter. P0363 records that protective mode. It usually appears with misfire codes P0300-P0312, which are the place to start diagnosis.

Symptoms

  • Rough, shaking engine operation
  • Noticeable loss of power and sluggish acceleration
  • Check Engine light on or flashing, especially under load
  • Poor fuel economy
  • Hesitation, stumbling or possible stalling
  • Vibration at idle
  • Increased exhaust emissions

Possible causes

  1. Worn or incorrect spark plugs
  2. Failed ignition coil or coil pack
  3. Faulty or clogged fuel injector
  4. Damaged wiring or poor connections at the coil or injector
  5. Low compression from valves, piston rings or head gasket
  6. Fuel delivery problems such as low pressure or bad fuel
  7. Vacuum leak in the intake

How to diagnose

  1. Read all codes and freeze frame data to identify the cylinder and conditions
  2. Check per-cylinder misfire counters with a scan tool
  3. Inspect the spark plug, coil, connector and wiring on the affected cylinder
  4. Swap the coil (and plug) with another cylinder and see if the misfire follows
  5. Test the injector: resistance, driver signal from the PCM, listen for clicking
  6. Check fuel pressure and look for intake vacuum leaks
  7. If electrical checks pass, run a compression test and a cylinder leak-down test if needed

Common fixes

  • Replace the spark plugs
  • Replace the failed ignition coil
  • Clean or replace the fuel injector
  • Repair damaged wiring or connectors
  • Repair the mechanical engine fault (head, rings, valves)
  • Clear codes after repair and confirm the misfire does not return

Questions and answers

What does P0363 mean?

The PCM found persistent misfires and cut fuel to the misfiring cylinder to protect the catalytic converter. The root cause is in the ignition, fuel system or engine mechanics.

Can I drive with code P0363?

Only a short distance at light load. The engine is running on fewer cylinders, and a mechanical cause can get worse with continued driving.

Where do I start fixing P0363?

Check for other misfire codes (P0300-P0312) to find the cylinder, then inspect that cylinder's spark plug and coil, which are the most common causes.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.