P0303 on Lincoln: How to Diagnose & Fix
Cylinder 3 Misfire Detected
4 Lincoln models · 4 documented issues · 2 critical · $100-$9,000 repair
P0303 on Lincoln by model: symptoms, diagnosis and fix
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.
Common Symptoms
- excessive oil consumption (1 quart per ~3000 miles)
- rough idle
- engine misfire
- blue or white exhaust smoke
- fouled spark plugs
- low oil warning between changes
How to Fix
Have the dealer confirm coverage under TSB 19-2243; the corrective procedure replaces both cylinder heads (and typically spark plugs). Monitor oil level frequently between services and document consumption to support a warranty/goodwill claim.
Sources for this issue (3)
- TSB 19-2243 (NHTSA MC-10164421): 2.7L/3.0L Oil Consumption With DTC P0524/P06DD, Rough Idle, Misfire, White or Blue Exhaust Smoke - 2016-2017 Edge/MKX, 2017 Continental/Fusion/MKZtsb
- Oil Consumption With DTC P0524 and/or P06DD - 2016-2017 Ford & Lincoln (OEMDTC)tsb
- Ford 2.7 EcoBoost Engine Specs, Problems, Reliabilityarticle
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.
Common Symptoms
- Check engine light, sometimes flashing, with misfire codes
- Rough or shaking idle
- Stumble or jerking under acceleration or load
- Reduced power and fuel economy
- Misfire worse in damp weather
How to Fix
Diagnose by swapping the suspect coil to another cylinder and confirming the misfire code follows; replace failed coils and boots, and replace high-mileage spark plugs at the same time. If coolant is found in a plug well, fix the intake manifold leak first or the new coil will fail too.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Motorcraft DG-508 ignition coil, singleOEMMotorcraft DG-508
Replace one coil confirmed failed on the 1998-2011 4.6L Town Car branch Fitment/availability: Live direct page identifies Motorcraft DG508, Town Car fitment and Add to Cart. Quantity is one per confirmed failed cylinder; confirm the vehi…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (4)
- Lincoln Town Car P0301: Cylinder 1 Misfire (Causes + How to Fix) — Drivetrain Resourcearticle
- How To Test The Coil-On-Plug Ignition Coils (1998-2011 4.6L Crown Victoria, Grand Marquis) — identical Panther 4.6L powertrain as Town Cararticle
- Ford DG508 Ignition Coil Failure: Misfires in 4.6L & 5.4L V8s (names Crown Victoria, Town Car, Grand Marquis) — Go-Partsarticle
- Cracking Intake Settlement (96M91/97M91 + class action, 1996-2001 4.6L incl. Town Car) — TCCoA Forumsforum
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.
Common Symptoms
- Repeated low-coolant warnings / disappearing coolant with no visible leak
- White smoke from the tailpipe (especially on cold start)
- Engine overheating / over-temperature warning in cluster
- Sweet coolant smell inside or outside the vehicle
- Rough idle and misfires (coolant-fouled plugs)
- Check engine light
How to Fix
Per TSB 20-2234, perform a cooling-system pressure test and inspect the EGR cooler; replace the EGR cooler and update PCM software for the typical case. If a coolant smell, white smoke, and cylinder misfires persist (coolant intrusion past the head gasket), the durable fix is a long-block / engine replacement with the updated cross-drilled block — a head-gasket-only repair on the old-style block will fail again. Replace fouled spark plugs and flush the cooling system.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Ford K2GZ-9F464-B EGR coolerOEMK2GZ-9F464-B
Replace a cooling-system-pressure-test-confirmed internally leaking EGR cooler under the matching TSB branch Fitment/availability: Live Ships in 1-3 Business Days/Add to Cart page identifies K2GZ-9F464-B, replacement of K2GZ-9F464-A and …
- Genuine Lincoln CYFS-12Y-PCTX / Motorcraft SP-550X spark plugOEMCYFS-12Y-PCTX / SP-550X
Confirm VIN
- Motorcraft Yellow prediluted antifreeze/coolant VC-13DL-G, 1 gallonOEMVC-13DL-G
Refill and bleed the repaired system with Ford-approved service coolant after the leak is corrected Fitment/availability: Live In Stock/Add to Cart direct page identifies Motorcraft VC-13DL-G one-gallon yellow prediluted coolant. Ford ap…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
P0303 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0303 mean on a 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 it is documented across 4 models: Navigator, MKX, Town Car, Nautilus.
What are the most common causes of P0303?
The most common causes of P0303 are: 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. The specific cause varies by vehicle.
How much does it cost to fix P0303 on a Lincoln?
Published repair estimates on Lincoln range from $100 to $9,000 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0303 on a different make?
View P0303 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.