Some 2018-2020 F-150 vehicles equipped with a 2.7L EcoBoost and 2020-2021 Expedition/Navigator vehicles may exhibit an illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTCs) P0420 and/or P0430 stored in the powertrain control module (PCM). This may be due to high sulfur content in the fuel. To correct the condition, follow the Service Procedure to de-sulfate the catalytic converters.
full bulletin at NHTSA ↗2021 Lincoln Navigator fuel system problems
moderate Owners of the 2021 Lincoln Navigator have filed 4 NHTSA complaints about the fuel system at roughly $1,200 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See fuel system across all vehicles →
When does it fail?
Of the 4 fuel system complaints filed for the 2021 Lincoln Navigator, here's the actual mileage breakdown — failures cluster heaviest at 50,000-75,000 mi.
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering fuel system on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
What owners are reporting 4 most recent
The contact owns a 2021 Lincoln Navigator. The contact stated that while the vehicle was parked, several attempts were needed to start the vehicle. The contact also stated that while driving at an undisclosed speed, the vehicle was shaking abnormally. There was no warning light illuminated. The contact received notification of NHTSA Campaign Number: 25V455000 (Fuel System, Gasoline). The vehicle…
The contact owns a 2021 Lincoln Navigator. The contact received notification of NTHSA Campaign Number: 25V455000 (Fuel System, Gasoline); however, the part to do the recall repair was not yet available. The local dealer was contacted. The dealer confirmed that the part was not yet available. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair.…
The contact owns a 2021 Lincoln Navigator. The contact received notification of NHTSA Campaign Number: 25V455000 (FUEL SYSTEM, GASOLINE); however, the part to do the recall repair was unavailable. The local dealer was contacted, and it was confirmed that the part was not yet available. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The…
The contact owns a 2021 Lincoln Navigator. The contact received notification of NHTSA Campaign Number: 25V455000 (Fuel System, Gasoline); however, the part to do the recall repair was not yet available. The dealer was not contacted. The contact stated that the recall was initiated for more than a year; however, the part to do the recall repair was still unavailable. The manufacturer was not…
Common questions
How serious is the fuel system problem on the 2021 Lincoln Navigator?
It's a documented issue but not catastrophic. 4 complaints have been filed. Repairs average $1,200 and most owners catch it before it causes a breakdown.
At what mileage does the fuel system typically fail?
Based on the 4 complaints filed, fuel system issues most often appear around 70,300 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $1,200 for fuel system repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to fuel system?
No active recalls currently cover fuel system issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.