P0311
Fix within a few daysCylinder 11 Misfire Detected
Code P0311 means Cylinder 11 is misfiring. Common causes: Spark plug (40%), ignition coil (30%), fuel injector (15%). Drivability: Yes, for short trips, but fix quickly. Repair cost: $50-$200 DIY, $150-$500 professional.
Can I Drive With P0311?
Yes, for short trips only
Essential trips under 10 miles, avoid highways and heavy acceleration. If the Check Engine Light is flashing, stop driving immediately.
Stop driving immediately if: Flashing Check Engine Light, loud knocking noises, burning smell, rotten egg smell from exhaust, significant power loss.
Symptoms of P0311
- 1Engine runs rough or shakes
- 2Loss of engine power
- 3Engine hesitates or stumbles during acceleration
- 4Check Engine Light is on, possibly flashing
- 5Reduced fuel economy
- 6Strong smell of raw fuel from the exhaust
Common Causes of P0311
Parts most likely causing this code, ranked by probability
A worn, fouled, or damaged spark plug in cylinder 11 prevents proper ignition of the fuel-air mixture.
40% of P0311 cases are fixed by replacing the spark plug
A faulty ignition coil for cylinder 11 fails to deliver sufficient voltage to the spark plug, causing a misfire.
30% of P0311 cases are fixed by replacing the ignition coil
A clogged or faulty fuel injector for cylinder 11 does not deliver the correct amount of fuel, leading to an improper air-fuel ratio and misfire.
15% of P0311 cases are fixed by replacing the fuel injector
Low compression in cylinder 11, caused by issues like worn piston rings, damaged valves, or a blown head gasket, prevents proper combustion.
10% of P0311 cases are fixed by addressing engine compression issues
Damaged wiring to the ignition coil or fuel injector, or a rare fault in the ECM, can disrupt the firing sequence for cylinder 11.
5% of P0311 cases are fixed by repairing wiring or replacing the ECM
Check These First (Before Buying Parts)
- Visually inspect the spark plug wire (if applicable) and ignition coil for cylinder 11 for any obvious damage, cracks, or corrosion.
- Listen for a distinct 'thump-thump' sound from the engine, indicating a misfire. You might also feel a vibration or shake.
How to Diagnose P0311
- 1Check for other related codes (P0300, P0301-P0310, P0312-P0316).
- 2Visually inspect the spark plug and ignition coil for cylinder 11 for damage or signs of wear.
- 3Swap the spark plug from cylinder 11 with a known good cylinder and recheck for the code. If the misfire moves, the spark plug is faulty.
- 4Swap the ignition coil from cylinder 11 with a known good cylinder and recheck for the code. If the misfire moves, the ignition coil is faulty.
- 5Listen to the fuel injector for cylinder 11 with a stethoscope to confirm it's clicking. Consider swapping it with another cylinder if accessible.
- 6Perform a compression test on cylinder 11 to check for internal engine issues.
- 7Check wiring continuity and voltage to the ignition coil and fuel injector for cylinder 11.
P0311 on Popular Vehicles
Ford F-150
2004-2024Ford F-150s are known for ignition coil failures and spark plug issues, especially on the 5.4L Triton engines where spark plugs can be difficult to remove. Fuel injector issues are also common.
75% fixed by replacing ignition coil or spark plug
Toyota Camry
2007-2024Misfires on Toyota Camry models are frequently traced back to ignition coils or spark plugs. Fuel injector issues are less common but do occur.
70% fixed by replacing ignition coil or spark plug
Honda Accord
2003-2024Honda Accord misfires, including P0311, are often caused by aging ignition coils or worn spark plugs. Valve adjustments can also sometimes resolve misfire issues on these engines if compression is low.
65% fixed by replacing ignition coil or spark plug
Frequently Asked Questions
What does P0311 mean?
P0311 indicates that your engine's computer has detected a misfire specifically in cylinder number 11. This means cylinder 11 is not firing correctly or contributing enough power to the engine.
Can I drive with P0311?
Yes, you can drive for short, essential trips if the Check Engine Light is solid. If the Check Engine Light is flashing, stop driving immediately. A flashing light indicates a severe misfire that is actively damaging your catalytic converter.
Will P0311 clear itself?
No, P0311 will not clear itself. The underlying issue causing the misfire must be diagnosed and repaired. Once the repair is complete, you can clear the code with a scan tool, or it will clear after several drive cycles if the problem is resolved.
How do I fix P0311 myself?
Start by inspecting and swapping the spark plug and ignition coil for cylinder 11 with a known good cylinder. If the misfire moves, replace the faulty part. If not, check the fuel injector for cylinder 11, and if that's not the issue, a compression test is the next step.
How much does it cost to fix P0311?
DIY costs range from $15-$30 for a spark plug, $50-$150 for an ignition coil, or $80-$250 for a fuel injector. Professional repair costs typically range from $150-$500, including parts and labor, depending on the specific component that needs replacement.
P0311 keeps coming back - why?
If P0311 keeps returning, it means the root cause was not correctly identified or fully resolved. This often happens if you only replaced one part (like a spark plug) when the actual issue was a different component (like the ignition coil or fuel injector), or a more serious underlying problem like low compression.
Will P0311 fail emissions/smog test?
Yes, P0311 will cause your vehicle to fail an emissions or smog test. A misfire means unburned fuel is entering the exhaust, which significantly increases harmful emissions and indicates a problem with the engine's combustion efficiency.
What's the difference between P0311 and P0300?
P0311 specifically indicates a misfire in cylinder number 11. P0300, on the other hand, means a 'Random/Multiple Cylinder Misfire Detected,' indicating misfires are occurring in more than one cylinder or are moving between cylinders, without pinpointing a single one.
P0311 on Ford F-150?
On Ford F-150s, P0311 is a common misfire code. The most frequent causes are faulty ignition coils or worn spark plugs, especially on higher mileage vehicles. Fuel injectors can also be a culprit, particularly if the truck has seen inconsistent fuel quality.
Questions to Ask Your Mechanic
Did you perform a compression test on cylinder 11?
Good answer: Yes, the compression on cylinder 11 is [X] PSI, which is within specification compared to the other cylinders.
What were the results of swapping the spark plug and ignition coil for cylinder 11?
Good answer: We swapped the spark plug and the misfire stayed on cylinder 11, then we swapped the coil and the misfire moved to cylinder [X], indicating a faulty coil.
Repair Cost Estimate
DIY Repair
Parts only
$15-$250
Shop Repair
Parts + labor
$150-$500
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - requires basic mechanical skills, an OBD-II scan tool, and specific tools like a spark plug socket. Diagnostic steps can be tricky for beginners.
Cost of Waiting
Continued misfires send unburned fuel into your exhaust system, which rapidly overheats and destroys your catalytic converter. A $50-$200 spark plug or coil job now prevents a $800-$2,500 catalytic converter replacement later.
While You're In There...
If your vehicle uses spark plug wires, they often wear out at the same rate as spark plugs and coils. Replacing them during the same repair prevents future misfires and repeat labor.
These rubber boots protect the coil and spark plug connection. They can degrade and cause arcing, leading to misfires. Replacing them with the coil or plugs is a low-cost preventative measure.
Applying dielectric grease to spark plug boots and electrical connections helps prevent corrosion and ensures a good electrical connection, extending the life of new components.
Tools You'll Need
- OBD-II Scan Tool
- Socket Wrench Set
- Spark Plug Socket (specific size for your vehicle)
- Torque Wrench
- Spark Plug Gap Tool (if replacing plugs)
- Dielectric Grease
- Multimeter (for electrical checks)
- Compression Tester (if needed)
- Fuel Injector Noid Light (if needed)
P0311 is a common misfire code. Most repairs are straightforward, involving a spark plug or ignition coil, and your engine will run smoothly again afterward.
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Your Next Steps
Step 1: Get an OBD-II scan tool to confirm P0311 and check for any other related codes. Note any other codes present.
Step 2: Perform a 'swap test' with the spark plug and ignition coil for cylinder 11. Move the spark plug to a different cylinder, clear the code, and see if the misfire follows. If not, swap the ignition coil. This helps pinpoint if the plug or coil is the culprit.
Step 3: If the misfire does not follow the spark plug or coil, the next likely culprit is the fuel injector for cylinder 11. You can test it with a noid light or by swapping it with another cylinder if accessible. If all these check out, perform a compression test on cylinder 11.