2008 Mercury Mountaineer Problems

What owners report

Owners of this model year most often describe the driver's power seat sliding back to its easy-exit position and the dome lights coming on while the vehicle is being driven, usually traced to the ignition switch or key tumbler. This appears across a wide mileage range, from nearly new to well past 100,000 miles, and complaints say the movement can put the pedals out of reach. Other recurring subjects include intermittent engine stalling, rough or delayed transmission shifting, and a few fuel or brake concerns.

1. 1
   Seats

   Driver's seat slides to easy-exit position while driving

   • 63 complaints (66%)
   • median 65,800 mi at 5.8 yrs old (56 state mileage)
   • 2 mention a crash, fire or injury
   • filed 2008–2019

   Owners describe the driver's power seat suddenly moving all the way rearward, as if the key had been removed, often with the dome or interior lights coming on at the same time. Many report it happens repeatedly on a daily basis and that a shorter driver can no longer reach the brake or accelerator pedals after the seat moves. According to complaints, dealers have replaced the ignition tumbler, the ignition electrical switch, the keyless entry module or the seat switch, and in several cases the movement returned after the repair. Reported from very low mileage up to roughly 150,000 miles, sometimes triggered by bumping the key or keychain or by driving over rough roads.

   1 related service bulletin

   What to check: Sit in the driver's seat with the engine running and gently wiggle the ignition key and keychain to see whether the seat moves or the dome lights flash. Ask the seller whether the ignition switch or tumbler has been replaced and whether the seat still moves on its own.

   2 excerpts from owner complaints in NHTSA records

   “While driving on the freeway, the driver's seat moved backwards. I was unable to reach the brake or gas and was nearly in an accident as I was unaware as to what was going on. The dome lights and the exterior exit lights lit up as well. Since this date, this has happened numerous times. It is a major safety issue and should become a recall.”

   NHTSA complaint #10498430, filed 2013-02, 57,000 miles

   “There is a recurring problem that the seat will automatically go into the easy exit position. This is not a problem for me as I drive with the seat as far back as possible, but this is a huge safety concern for my wife. Why hasn't this been recalled yet? This seems to be a common problem in this make and model. God forbid the electrical problem worsens and causes a fire.”

   NHTSA complaint #10549236, filed 2013-10, 29,000 miles
2. 2
   Engine

   Intermittent no-start, stalling and rough running

   • 13 complaints (14%)
   • median 83,200 mi at 6.9 yrs old (12 state mileage)
   • filed 2010–2025

   Owners describe the engine cutting out or failing to restart, sometimes needing several attempts or a wait before it will start again, and in some cases stalling while driving or at a stop. A few mention misfiring and shaking or spark plugs that required special tools to remove. Complaints say dealers were often unable to duplicate the problem, though some repairs involved the ignition switch or battery. Scattered from under 20,000 miles to past 130,000 miles, with no clear mileage pattern.

   4 related service bulletins

   What to check: Start the vehicle several times from cold and from warm and watch for a rough idle or a dip in rpm when coming to a stop. Ask whether the engine harness and throttle body have been checked under the relevant service bulletin.

   2 excerpts from owner complaints in NHTSA records

   “Takata recall while my vehicle is in motion, & when I stop at a stop light, it's suddenly shuts off. This has happened several times while on the highway at highway speeds, & on city streets at normal speeds. It has proven dangerous several times. When I put the vehicle in reverse, the vehicle jerks very hard. Also when I drive for more than 6 to 7 miles at highway speeds, a tire pressure sensor comes on.”

   NHTSA complaint #11196908, filed 2019-04, 129,000 miles

   “Vehicle is missing, now shaking. Need spark plug replaced but is stuck. Needed special tool/equipment to get out. Will be very costly. I shouldn't have to have this problem since I only purchased it almost 2 yrs ago. I am really contemplating suing!!”

   NHTSA complaint #10496692, filed 2013-02, 86,400 miles
3. 3
   Transmission and drivetrain

   Rough or delayed transmission shifting

   • 12 complaints (13%)
   • median 38,319 mi at 4.2 yrs old (9 state mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2010–2025

   Complaints describe the transmission hesitating to change gears at low speed or jerking hard when it does shift, and one owner reports a transmission that eventually failed during highway driving. Another notes the gear shifter intermittently failing to move to the intended position. According to complaints, dealers sometimes reprogrammed the control module or could not reproduce the symptom. Mostly reported between about 28,000 and 70,000 miles.

   Recall 07V4530002 related service bulletins

   What to check: Test drive at low speed and watch for hesitation or a hard jolt between gears, and check for a delayed engagement when shifting from park to drive or reverse. Ask about transmission fluid service history and whether the recall on the transmission cooler line bolt was completed.

   2 excerpts from owner complaints in NHTSA records

   “At 28000 miles the transmission started shifting erratic, the dealer reprogrammed the ECM and covered up the problem until the warrant ended and the battery failed at which time the car reverted back to default and continued to buck and jerk until the car reached highway speed. This continued until the transmission finally failed during operation on the highway on 3/5/20. The ABS module just failed during low speed operation for no apparent reason. …”

   NHTSA complaint #11316784, filed 2020-03, 29,000 miles

   “The contact owns a 2008 Mercury Mountaineer. While in park and turned off, the vehicle rolled forward and collided with another vehicle. There were no warning indicators illuminated or injuries. A police report was filed. The vehicle was taken to a dealer, but was not diagnosed. The manufacturer was made aware of the failure. The failure mileage was 70,500.”

   NHTSA complaint #10903893, filed 2016-09, 70,500 miles

Buying note. Before buying, drive the vehicle and deliberately wiggle the ignition key to check whether the driver's seat moves on its own, since that is the most common complaint for this year. Also test the transmission at low speed and check the brake pedal feel, and ask for service records on ignition switch and transmission work.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.