P0305 on Lincoln
Cylinder 5 Misfire Detected
P0305 on Lincoln vehicles indicates cylinder 5 misfire detected. Au7o has documented this code across 2 Lincoln models — most commonly on MKX, Navigator. This code means the engine control module detected a misfire on cylinder number 5, meaning that cylinder is not burning its air-fuel mixture properly on some combustion cycles. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder fails to fire correctly. A misfire wastes fuel, can make the engine run rough or shake, and dumps unburned fuel into the exhaust, which can overheat and damage the catalytic converter. It generally points to a problem with spark, fuel delivery, or compression specifically affecting cylinder 5. Typical repair costs on Lincoln range from $400 to $8,000, depending on the specific model and root cause.
Common Causes of P0305
- •Worn or fouled spark plug on cylinder 5
- •Failed ignition coil or coil pack for cylinder 5
- •Faulty or clogged fuel injector on cylinder 5
- •Vacuum or intake air leak affecting that cylinder
- •Bad spark plug wire or boot (on applicable engines)
- •Low compression from worn rings, valves, or head gasket
- •Carbon buildup or sticking valve on cylinder 5
- •Lean or rich fuel condition affecting the cylinder
P0305 on Lincoln by Model
Lincoln MKX(1 issue)
- 2.7L EcoBoost Excessive Oil Consumption from Faulty Valve Guides2016-2017
2016-2017 Lincoln MKX models with the 2.7L EcoBoost V6 (engines built roughly April 2016 to January 2017) can suffer excessive oil consumption caused by defective cylinder head valve guides that let oil seep into the combustion chamber and burn off. Owners report burning roughly a quart every 3,000 miles, often accompanied by rough idle, misfires, and blue/white exhaust smoke. Ford addressed this in Technical Service Bulletin 19-2243, whose official remedy is replacement of both left and right cylinder heads. Fouled spark plugs from oil contamination commonly trigger cylinder-specific misfire codes.
Lincoln Navigator(1 issue)
- Navigator 5.4L 3V Triton Spark Plug Breakage on Removal2005-2008
The 5.4L 3-valve Triton V8 in 2005-2008 Navigator (and shared F-150/Expedition) uses a two-piece spark plug (Motorcraft SP-515/SP-546) that frequently snaps off in the cylinder head during removal. The lower portion stays welded into the head by carbon, leaving the upper electrode in the socket. Common at 60,000-100,000 miles when the first plug change is attempted.
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View P0305 across all makes →Frequently Asked Questions
What does P0305 mean on Lincoln?▼
P0305 stands for "Cylinder 5 Misfire Detected." This code means the engine control module detected a misfire on cylinder number 5, meaning that cylinder is not burning its air-fuel mixture properly on some combustion cycles. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder fails to fire correctly. A misfire wastes fuel, can make the engine run rough or shake, and dumps unburned fuel into the exhaust, which can overheat and damage the catalytic converter. It generally points to a problem with spark, fuel delivery, or compression specifically affecting cylinder 5. On Lincoln specifically, this code is documented across 2 models.
What causes P0305 on Lincoln vehicles?▼
Common causes on Lincoln: Worn or fouled spark plug on cylinder 5, Failed ignition coil or coil pack for cylinder 5, Faulty or clogged fuel injector on cylinder 5, Vacuum or intake air leak affecting that cylinder, Bad spark plug wire or boot (on applicable engines). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0305 on a Lincoln?▼
Repair costs on Lincoln range from $400 to $8,000, depending on the specific model and root cause.
Which Lincoln models have P0305 documented?▼
Au7o has documented P0305 on 2 Lincoln models: MKX, Navigator.