P0311 code: Cylinder 11 Misfire Detected
P0311 means cylinder 11 Misfire Detected. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0311 means
P0311 means cylinder 11 is misfiring — failing to burn its air-fuel charge reliably. A cylinder 11 only exists on twelve-cylinder engines (and rare configurations beyond ten), so in practice this is a V12 code found on high-end luxury and performance cars. The diagnostic logic is the same as any single-cylinder misfire: the leading causes are that cylinder's spark plug or ignition coil, verified by swapping the part to a neighboring cylinder and watching whether the misfire follows. A weak or clogged fuel injector and low compression are the less common possibilities. V12s mask single-cylinder misfires well — the engine can feel nearly smooth — but the unburned fuel still overheats the catalytic converter on that bank, and V12 catalyst hardware is among the most expensive to replace. Cylinder numbering varies by manufacturer, so confirm which cylinder is 11 before pulling parts.
P0311 symptoms
- Slight roughness or vibration, often subtle on a V12
- Reduced power or hesitation under load
- Flashing check-engine light during an active misfire
- Reduced fuel economy
- Fuel smell from the exhaust in severe cases
What it costs to fix P0311
Varies by vehicle — get it diagnosed.
The repair cost for this code depends too much on your exact vehicle and the underlying cause to quote a meaningful range. Confirm the cause first so you only pay for the fix you actually need.
Diagnose P0311 for my vehicle →How to fix P0311
Moderate — doable at home with common tools and patience
- Confirm a V12 or W12 and locate cylinder 11
A cylinder 11 means a twelve-cylinder engine — a V12 or a W12 — and both layouts number their cylinders in maker-specific ways. Work from the diagram for your exact engine; on a W12 in particular, the staggered rows make it easy to count to the wrong cylinder.
- Scan every engine module, not just one
Some twelve-cylinder engines split engine management between two control modules, roughly one per bank, and a basic reader may only talk to one. Use a scanner that sees both, save the freeze frame, and check whether that bank's fuel trims are off or whether cylinder 11 is the only one logging misfires.
- Exchange coil 11 with a healthy neighbor
Move cylinder 11's coil to a neighbor that runs clean, reset the codes, and drive under the freeze-frame conditions. A miss that migrates with the coil settles it; one that stays on 11 points to the plug, injector, or the cylinder itself. Where an engine runs two plugs per cylinder, check both coils or outputs serving it.
- Renew the cylinder 11 plug, or plugs
Look for a cracked insulator, heavy deposits, or oil from a seeping cam cover gasket sitting in the well. Plugs on many twelve-cylinder engines stay in long past the scheduled interval because of the labor involved, so if the set is old, doing the whole bank now avoids pulling the covers twice.
- Test injector 11 and compression before big spending
Compare injector 11's resistance or pulse with its neighbors, and on direct-injection engines leave injector removal to a shop. If spark and fuel are both good, a compression or leak-down test backed by a borescope look into the cylinder decides whether this is mechanical — on an engine where internal work is very expensive.
DIY or shop? Diagnosis is approachable if you own a scanner that talks to every engine module on the car — that alone answers a lot. Whether the coil swap and plug change are DIY depends on packaging: on some V12s the coils sit under covers on top of the heads and come out with basic tools, while on others intake parts have to come off first. Twelve-cylinder parts are pricey, so avoid guess-buying; once the job needs intake removal, injector work, or a leak-down test, a shop that knows these engines is the better call.
Tools for the DIY steps: Scanner that reads all engine modules · Thin-wall spark plug socket · Trim and cover removal tools · Torque wrench · Borescope · Compression tester
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0311.
Start a case with P0311 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0311?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0311: common questions
What vehicles get P0311?
Only engines with eleven or more cylinders — effectively V12s in luxury and performance cars. If a smaller engine shows this code, suspect a scan-tool misread or a spurious stored code and re-scan before doing anything else.
The engine feels fine — do I still need to fix it?
It does. A V12 hides one dead cylinder well, but the misfiring cylinder is still pushing unburned fuel into the exhaust, which overheats the catalytic converter over time. Catching it while it's a plug or coil is far cheaper than adding a catalyst to the bill.
Is it the coil, the plug, or the injector?
Statistically the plug or coil. Swap the suspect coil (or plug) with a neighboring cylinder and clear the code — if the misfire follows the part, you've found it. If it stays on cylinder 11, test the injector and then compression.
Can I drive with P0311?
Redline can't make that call from the code alone. With a steady light, arrange the repair promptly — the misfire is feeding raw fuel to the catalytic converter the whole time. A flashing light means an active, catalyst-damaging misfire — stop driving and have it diagnosed or towed.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0311 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0311 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.