Cylinder 11 Misfire Detected
Diagnostic trouble code P0311 indicates that the engine control module (ECM) has detected a misfire in cylinder 11. A misfire occurs when the air-fuel mixture in the cylinder fails to ignite properly, causing a loss of power, increased emissions, and potential damage to the catalytic converter. This code is typically triggered when the crankshaft position sensor detects irregularities in engine speed during cylinder 11's power stroke.
01. Most Common Causes
- Faulty spark plug or ignition coil on cylinder 11
- Fuel injector issue (clogged, leaking, or electrical)
- Vacuum leak or intake manifold gasket leak
- Low compression due to worn piston rings or valves
- Engine control module (ECM) software or wiring problem
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire, rough idle, or hesitation
- Reduced power and fuel economy
- Possible catalytic converter overheating
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Inspect spark plug and ignition coil on cylinder 11; swap with another cylinder to see if misfire follows.
Step 3: Check fuel injector pulse and resistance; perform a cylinder balance test.
Step 4: Test compression on cylinder 11 and compare to others.
Step 5: Inspect for vacuum leaks using smoke machine or propane enrichment.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with a misfire, as it can damage the catalytic converter and other engine components. Short trips to a repair shop are acceptable if the engine is not overheating or severely shaking.
How much does it cost to fix?▼
The cost varies depending on the cause. A spark plug or coil replacement can cost $50-$150 per part, while fuel injector or compression repairs may range from $200-$1000 or more.