P0303 on Lincoln
Cylinder 3 Misfire Detected
P0303 on Lincoln vehicles indicates cylinder 3 misfire detected. Au7o has documented this code across 4 Lincoln models — most commonly on MKX, Nautilus, Navigator. This code means your engine's computer detected a misfire specifically in cylinder number 3 — that cylinder isn't burning its fuel-air mixture properly or completely. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder is supposed to fire. A misfire wastes fuel, can cause a noticeable shake, rough idle or loss of power, and can flood raw fuel into the exhaust where it may overheat and damage the catalytic converter. Because the fault is isolated to one cylinder, the cause is usually something specific to that cylinder's ignition, fuel delivery, or compression. Typical repair costs on Lincoln range from $100 to $9,000, depending on the specific model and root cause.
Common Causes of P0303
- •Worn or fouled spark plug in cylinder 3
- •Failed or weak ignition coil on cylinder 3
- •Bad spark plug wire or boot (where applicable)
- •Clogged or leaking fuel injector for cylinder 3
- •Vacuum or intake air leak affecting that cylinder
- •Low compression (worn rings, burnt/leaking valve, head gasket)
- •Wiring or connector fault at the coil or injector
P0303 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 Nautilus(1 issue)
- 2.0L EcoBoost coolant loss / EGR cooler leak — low coolant, white smoke, overheat2019-2020
2019-2020 Nautilus models with the base 2.0L EcoBoost (non-hybrid) suffer unexplained coolant loss, white tailpipe smoke, an overheat warning, and sometimes coolant intrusion into the cylinders. Ford TSB 20-2234 traces the most common cause to a failing exhaust gas recirculation (EGR) cooler that leaks coolant internally; the related design also has a known coolant-intrusion weakness (narrow coolant slit between cylinders compromising the head-gasket seal). Owners report repeated coolant top-offs with no visible external leak, then misfires as coolant fouls the plugs. A June 2025 Ford EcoBoost coolant-intrusion class action covers 1.5L-2.0L engines; the most severe Nautilus cases require engine replacement with the redesigned block.
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.
Lincoln Town Car(1 issue)
- Coil-on-Plug Ignition Coil Failure and Misfires (4.6L V8)1998-2011
The 1998-up 4.6L 2V V8 uses eight individual coil-on-plug ignition coils whose boots and towers crack with age and heat, allowing spark to track to ground and causing single- or multi-cylinder misfires, rough idle, and stumbling under load. Failures are accelerated when the 1996-2001 plastic intake manifold leaks coolant into the spark plug wells and shorts the coils. It is one of the most common drivability complaints on the platform, well documented across owner forums and diagnostic guides.
Looking for P0303 on a different make?
View P0303 across all makes →Frequently Asked Questions
What does P0303 mean on Lincoln?▼
P0303 stands for "Cylinder 3 Misfire Detected." This code means your engine's computer detected a misfire specifically in cylinder number 3 — that cylinder isn't burning its fuel-air mixture properly or completely. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder is supposed to fire. A misfire wastes fuel, can cause a noticeable shake, rough idle or loss of power, and can flood raw fuel into the exhaust where it may overheat and damage the catalytic converter. Because the fault is isolated to one cylinder, the cause is usually something specific to that cylinder's ignition, fuel delivery, or compression. On Lincoln specifically, this code is documented across 4 models.
What causes P0303 on Lincoln vehicles?▼
Common causes on Lincoln: Worn or fouled spark plug in cylinder 3, Failed or weak ignition coil on cylinder 3, Bad spark plug wire or boot (where applicable), Clogged or leaking fuel injector for cylinder 3, Vacuum or intake air leak affecting that cylinder. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0303 on a Lincoln?▼
Repair costs on Lincoln range from $100 to $9,000, depending on the specific model and root cause.
Which Lincoln models have P0303 documented?▼
Au7o has documented P0303 on 4 Lincoln models: MKX, Nautilus, Navigator, Town Car.