P0311 Cylinder 11 Misfire Detected

P0311 indicates a misfire detected on cylinder 11. Cylinder 11 is not contributing smoothly enough during the monitor window.

Code details

Generic OBD-II · P0

System: Ignition / Misfire
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not ignore a cylinder 11 misfire if catalyst temperature or flashing MIL symptoms are present.

Symptoms of P0311

Rough idle, shaking, or a stumble under acceleration.
A flashing check-engine light during an active misfire.
Power loss and higher fuel consumption.

Common causes of P0311

Worn spark plugs, ignition coils, or plug wires.
Fuel-delivery problems — injectors, pressure, or a lean/rich mixture.
Vacuum leaks, low compression, or a mechanical fault in that cylinder.

Useful checks before replacing parts

Compare cylinder 11 misfire counters with injector balance, ignition command, fuel trims, compression, and freeze-frame operating conditions.
Inspect cylinder 11 ignition or glow parts, injector operation, wiring, air leaks, compression, fuel quality, and exhaust condition.
Check whether the misfire follows temperature, load, RPM, moisture, or related injector circuit and contribution codes.

Related OBD-II codes

These nearby ignition / misfire entries can help compare wording and pin down the fault area.