Acceleration complaints by model year
| Year | Complaints | Share of year's complaints | Typical mileage |
|---|---|---|---|
| 2010 | 4 | 31% | 38,000 miles |
| 2009 | 1 | 17% | 47,000 miles |
| 2008 | 2 | 2% | 38,000 miles |
| 2007 | 7 | 9% | 39,000 miles |
| 2006 | 3 | 3% | 48,000 miles |
| 2005 | 13 | 16% | 40,000 miles |
| 2004 | 21 | 10% | 80,000 miles |
| 2003 | 9 | 6% | 93,000 miles |
| 2002 | 18 | 5% | 67,000 miles |
| 2001 | 2 | 9% | — |
| 2000 | 28 | 23% | 102,000 miles |
| 1999 | 11 | 7% | 79,000 miles |
| 1998 | 36 | 15% | 100,000 miles |
| 1997 | 59 | 18% | 110,000 miles |
Which parts fail
Components named in complaints (accelerator pedal, throttle, sudden acceleration, cruise control).
Mileage when the problem started
What owners report
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.
There is a manufacturing fault with the position of the brake and the gas pedal. It is very easy to move the right foot from the gas to the brake and leave enough of the foot on the gas at the same time. It allows the brake to be pressed but also applies gas to give a vehicle a surge while braking. Had the same situation with a 2001 Ford taurus and Ford issued a recall notice to have the placement of pedals changed.
My 2007 Mercury Mountaineer never had any problems until recently, thought it was the transmission because of the way it drove. Took it to the mechanic and got transmission fluid put in but the problems remained the same and was told the transmission was fine. My thermostat housing unit was leaking (this is very common with these cars and very dangerous, needs immediate attention!) and had caused very expensive wiring issues. Almost acts exactly like the transmission is going out - RPM's are way too high, the vehicle would not accelerate in the middle of city traffic, the car jumped at a stoplight and caused me to hit the car in front of me, and it doesn't shift properly. Problems occurred out of nowhere and are too dangerous to be ignored but very expensive to be fixed. Its very common and should be recalled before someone gets seriously injured!!!!
Tl contact owns a 2007 Mercury Mountaineer. Immediately after the vehicle was turned on without warning, it accelerated and crashed into a store. The police gave her a ticket for careless driving. The vehicle was towed to an authorized dealer. She was not informed of the repairs that were made to the vehicle. The contact has had problems with the vehicle since she purchased it. Prior to the failure, whenever she engaged the brake pedal the vehicle accelerated without warning; however, the dealer stated that there was nothing wrong with the vehicle. The vehicle was destroyed per the insurance company. The contact was always concerned about the safety risk and defect in the vehicle . The failure and current mileages were 30000. Updated 11/04/09. The consumer stated the vehicle made a noise when the gear was placed in reverse. Updated 11/05/09
My 2006 Mercury Mountaineer has intermittently jolted or lurched forward when stopping for lights and stop signs after speeds over 30 MPH. Hasn't gotten away from me but feels as if I am going to hit something or someone ahead of me. Extremely scary when people are in cross walk. I took my car to the Ford dealer shortly after buying it used. The dealer checked it out and denied it was happening. That was years ago and tonight I saw numerous complaints on another website about this problem. Was looking because now I am getting a grinding noise from my wheels which persists after a brake job that didn't fix it as I thought. Both problems are separate but I see a pattern of them on this vehicle now.
Tl* the contact owns a 2006 Mercury Mountaineer. The contact stated while attempting to accelerate from a complete stop, the pedal was abnormally resistant and the vehicle would not respond. The engine was turned off and when restarted, the vehicle resumed normal operation. The failure recurred three times intermittently. The vehicle was taken to the dealer where the technician was unable to diagnose the failure. The vehicle was not repaired. The approximate failure mileage was 48,000.
started losing power ,did not want to go pas 30 miles per hr ,then it ramed up and came to a stop with no acceleration ,i shut it off then start it again and was able to get home at a low rate of speed while continuing to have these problems, another day while far away from home the engine rammed up again minimizing my speed as the transmission was slipping and not go fast then my O/D over drive went on flashing a light ,while the engine kept steady at 20-30 miles per hour while accelerating increasing no speed ,now my SUV will not run wright, it will kick into gear at times constantly and cause problems driving safely ,this is a common problem I'm hearing and reading in the internet with the ford/ mercury mountaineer the manufactory does not want to accept responsibility with this problem ..... …
I purchased a used 2005 Mercury Mountaineer last month, with 135,400 miles, while using cruise control and traveling approximately 35 MPH, the road went from level to a very slight downgrade. The car then just shut off after audible warning bell was heard. Noticed dashboard lights were all lit and battery gage was normal. I lost power steering, brakes and oil pressure. After pulling safely to the side of the road, I rested for 30 seconds before restarting the car, which subsequently operated normally. After taking it in for an oil change and safety check, I went on a 450 mile weekend trip and had no issues, restricting cruise control to highway speeds. The other day, I was traveling on a different stretch of level road in my town while using cruise control at approx. 35 MPH. After heading into a slight downgrade, I again heard the warning bell, followed by engine shut off. …
Related recalls (6)
Vehicle speed control
Ford is recalling model years 1995-2003 windstar, 2000-2003 excursion diesel, 1993-1997 and 1999-2003 f-250 sd through f-550 sd diesel, 1992-2003 e-150 through e-550, 1995-2002 explorer, 1997 and 2002 Mercury mountaineer, 1995-1997 and 2001-2003 ranger, and 1994 f53 vehicles equipped with the texas instruments speed control…
Remedy: Ford will notify owners that dealers will install a fused wiring harness in line with the scds. On 1999-2003 windstar vehicles with a leaking scds, dealers will also inspect the ABS control module connector and repair…
Vehicle speed control
On certain pickup trucks, passenger vehicles, sport utility vehicles, and motor homes chassis, the speed control deactivation switch May, under certain conditions, leak internally and then overheat, smoke, or burn.
Remedy: Dealers will install a fused wiring harness. Owners of the passenger cars included in this campaign will be instructed to return their vehicles to their dealers to have the speed control deactivation switch disconnected…
Vehicle speed control › Cables
On certain sport utility vehicles equipped with speed control and 4.0l sohc engines, if the strand cover on the speed control cable becomes flared at the end, the speed control cable May bind when the speed control is activated.
Remedy: Dealers will inspect the speed control cable and, if necessary, replace it. Owner notification began August 29, 2003. Owners should contact Ford at 1-800-392-3673.
Vehicle speed control
Vehicle description: sport utility vehicles equipped with 4.0l sohc engines and still retain the original throttle body (part numbers 97jf-9e926ab or 97jf-9e926-ac). Some of the original throttle bodies installed allowed a gap between the plate and bore to be built too narrow.
Remedy: Dealers will replace the original throttle bodies.
Vehicle speed control
Vehicle description: certain 1997-1999 rhd explorer equipped with 4.0l ohv/sohc engines and cruise control built from May 29, 1996 through March 4, 1999; 1998-1999 explorer/mountaineers equipped with 4.0l ohv/sohc or 5.0l engines or 1998-1999 rangers equipped with 2.5l, 3.0l ffv/efi or 4.0l engines and cruise control built from…
Remedy: Dealers will replace the cruise control cables. At the present time, the replacement cables are not available. Customers are being advised not to use the cruise control system until a replacement can be made.
Show 1 more recall
Vehicle speed control
Vehicle description: multi-purpose passenger vehicles equipped with 5.0l engines originally sold or currently registered in the states of alaska, idaho, iowa, maine, michigan (upper peninsula only), minnesota, montana, nebraska, new hampshire, new york, north dakota, south dakota, vermont, wisconsin, and wyoming.
Remedy: Dealers will install a revised pcv system with water heated vacuum source.
NHTSA investigations
Stuck engine throttle
On July 7, 2005, the office of defects investigation (odi) opened a preliminary evaluation to investigate alleged stuck throttle complaints in certain model year (my) 2002 Ford explorer and Mercury mountaineer vehicles equipped with the standard available 4.0l sohc v6 engine.at that time, odi was aware of 15 complaints that alleged stuck engine throttle causing unwanted vehicle acceleration and 1 alleged crash as a…
Frequently asked questions
Which Mercury Mountaineer years have acceleration problems?
By NHTSA complaints, the 1997 (59), 1998 (36), 2000 (28), 2004 (21) and 2002 (18) model years. Acceleration complaints make up 18% of all complaints for the 1997.
Is there a recall for Mercury Mountaineer acceleration problems?
Yes — 6 recalls, including 09V-399 (vehicle speed control, Oct 13, 2009); 07V-336 (vehicle speed control, Aug 3, 2007); 03V-280 (cables, Aug 5, 2003). Recall repairs are free at authorized dealers; check a specific car with the VIN recall check.
At what mileage do Mercury Mountaineer acceleration problems start?
Across all years, half of the complaints with a recorded mileage happened before about 78,000 miles; 34% happened before 50,000 miles.
What part fails most often?
Owners most often name the accelerator pedal (50 mentions), followed by the cruise control (19).
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.