There are 2 stored owner reports matching the fuel system leading-label group for the 2003 Mercury Mountaineer in our NHTSA-sourced dataset. These are unverified consumer reports and may not reflect confirmed defects.
This group counts stored reports whose component label starts with one of this site's matching prefixes, ignoring case. Each matching report counts once within the group. Components mentioned later in the label or only in the narrative are not searched. How component counts work
Loaded 2 of 2 matching reports.
Open the full vehicle complaint log (all categories)TL* THE CONTACT OWNS A 2003 MERCURY MOUNTAINEER. WHILE DRIVING AT VARIOUS SPEEDS, THE VEHICLE SUDDENLY SHUT OFF. THE VEHICLE WAS TAKEN TO AN INDEPENDENT MECHANIC WHO DIAGNOSED THAT THE FUEL PUMP WAS FAULTY. THE FUEL PUMP WAS REPLACED, BUT THE FAILURE CONTINUED. NO FURTHER INFORMATION WAS AVAILABLE. THE MANUFACTURER WAS NOT NOTIFIED OF THE FAILURE. THE FAILURE MILEAGE WAS 113,000.
2003 MERCURY MOUNTAINEER 4.6L-V8: WHEN THE VEHICLE IS NOT UNDER ACCELERATION [STOP SIGN/SIGNAL, EXITING AN EXPRESSWAY TO A SURFACE STREET, COASTING] THE ENGINE WILL NOT HOLD IDLE, THEN STALL. THE STEERING & BRAKES ARE COMPROMISED WHEN THE ENGINE STALLS. TO RESTART THE ENGINE, THE HEADLIGHTS GO DARK FOR A MOMENT...THIS IS A VERY SERIOUS MATTER. DECELERATING FROM AN EXPRESSWAY TO A SURFACE STREET, ON A CURVED EXIT RAMP , AT NIGHT MAKES FOR AN OUT OF CONTROL SITUATION WHERE THE DRIVER CAN NOT SEE BECAUSE OF ENGINE FAILURE! I'VE REPLACED THE THROTTLE POSITION CENSOR [TPS] WITH NO IMPROVEMENT. THE DEALER OFFERS REPLACEMENT OF PARTS $1500, AND NO GUARANTEE OF SOLVING THE PROBLEM. THE VEHICLE IS USELESS TO ME FORE IT IS A HAZARD TO BE ON THE ROAD...FOR ME AND ANYONE ELSE DRIVING NEAR ME. *TR
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
NHTSA source checks for this vehicle year
Checks are recorded separately for each dataset, not for the whole page. Dates use UTC. A missing check date does not mean no records exist.
Vehicle import recorded: Apr 28, 2026. This is the stored import date, not confirmation that every source was successfully refreshed.