Acceleration complaints by model year
Which parts fail
Components named in complaints (accelerator pedal, throttle, sudden acceleration, cruise control).
Mileage when the problem started
What owners report
Our 18 year old daughter who has a permit was driving our 2007 monetego one evening with me. When she went to park at a drive inn restaurant under my guidance, she was pulling into a parking space and the car unexpectedly lunged forward. As an inexperienced driver she panicked and took her foot off the brake - endangering the lives of at least 10 people that were eating at the picnic tables outside of the restaurant. Thankfully the car was going at a relatively low speed and the curb stopped its forward motion. I had noticed intermittent "lunging" when I applied the brakes just a few times before this and a clunking when shifting and I had already taken it to my local mechanic who checked the transmission and brakes but said they were fine. After the incident with my daughter we took the car to the dealer and they said that the throttle body is bad. …
I have experienced a sudden unexpected lunge when backing out of a parking space after placing the vehicle in reverse on several occasions. You can hear the engine RPM increase quickly, then decrease just as quickly when this happens. This typically occurs when the vehicle is placed in reverse and the wheel is being turned and the my foot is on the brake pedal. It has also occurred again when the vehicle is put into drive after going from reverse and the wheel is turned. Having the brake pedal depressed, is effective in stopping the vehicle, but since the timing and circumstances of the malfunction is unpredictable, it has become a noticeable and constant issue. I thought my vehicle was an isolated issue, but it appears to be more widespread. …
The contact owns a 2006 Mercury Montego. The contact stated that while parallel parking, the vehicle independently accelerated and lunged forward. There were no warning lights illuminated. The contact stated that the failure was due to the throttle body. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The failure mileage was approximately 80,000.
The throttle control transmission has failed me several times when I'm on the road. Thankfully it's only left me stranded on the side of the freeway once but has made me stop during oncoming traffic several times. The wrench light comes on when the vehicle decelerates and I'm unable to accelerate. Once the steering wheel even locked. This happens at random times but because the code is pending mechanics can't seem to find the issue. This has happened dozens of time where it just stops suddenly while driving. I am concerned for the safety of me and my family when driving this vehicle. Please get this issue resolved!
Tl* the contact owns a 2005 Mercury Montego. While attempting to depress the brake pedal, the vehicle began to accelerate and the traction control, check transmission, and failed safe mode warning lights illuminated. Due to the failure, the contact crashed into a bush while attempting to park the vehicle. There were no injuries and a police report was not filed. The failure recurred randomly. The vehicle was taken to several independent mechanics, but the cause of the failure could not be determined. The vehicle was not repaired. The manufacturer was notified. The failure mileage was approximately 270,000.
Tl* the contact owned a 2005 Mercury Montego. While driving approximately 30 MPH, the vehicle experienced unintended acceleration and crashed into the rear of a second vehicle. Prior to the failure, the engine rpms erroneously increased and the vehicle surged forward. The front end of the vehicle sustained severe damage, but the air bags did not deploy. The vehicle was destroyed and towed. There were no injuries and a police report was filed. The manufacturer was notified of the failure. The local dealer was not notified. The failure mileage was 150,000.
NHTSA investigations
Idle instability
On November 29, 2012, Ford Motor Company (Ford) initiated Customer Satisfaction Program 12N03 to extend warranty coverage terms for repair of engine idle RPM surge caused by throttle body deposits in all model year (MY) 2005 through 2007 Ford Freestyle, Five Hundred and Mercury Montego vehicles.The program extends the coverage for up to 10 years of service or 150,000 miles from the warranty start date of the vehicle…
Frequently asked questions
Which Mercury Montego years have acceleration problems?
By NHTSA complaints, the 2005 (24), 2006 (14) and 2007 (12) model years. Acceleration complaints make up 18% of all complaints for the 2005.
Is there a recall for Mercury Montego acceleration problems?
No. NHTSA lists no speed control & acceleration recall for any Mercury Montego model year. A widespread problem may still be covered by an extended warranty or a manufacturer service bulletin, so ask a dealer.
At what mileage do Mercury Montego acceleration problems start?
Across all years, half of the complaints with a recorded mileage happened before about 84,000 miles; 15% happened before 50,000 miles.
What part fails most often?
Owners most often name the accelerator pedal (1 mentions).
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.