There are 1 owner-reported fuel system complaints for the 2010 Mercury Mountaineerin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
WHILE DRIVING THE MOUNTAINEER I WAS SLOWING FOR A STOPLIGHT SHORTLY AFTER STARTING IT UP (HAD DRIVEN ABOUT 1/3 MILE). THE ENGINE SUDDENLY STARTED TO SPEED UP AND REQUIRED SIGNIFICANT EXTRA BRAKING FORCE TO COME TO A STOP. I PUT THE CAR IN NEUTRAL AND THE ENGINE RAN AT ABOUT 3,300 RPM FOR ABOUT 10 SECONDS. THIS IS THE THIRD TIME THIS HAS HAPPENED. THE FIRST TIME THE THERMOSTAT WAS REPLACED. THE SECOND TIME THE THROTTLE BODY WAS REPLACED. THE THIRD TIME THE VEHICLE WAS CHECKED BUT NO DEFECT COULD BE FOUND. THE SECOND TIME I ALSO PUT IT IN NEUTRAL AND IT ALSO RAN AT ABOUT 3,300 RPM FOR ABOUT 10 SECONDS. *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.
Data synced from NHTSA on Apr 26, 2026