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.
2005 Mercury Montego acceleration problems
24 complaints (18% of all complaints for this car). Typical mileage when it fails: 86,000. 2 crashes reported.
- owner complaints
- 24
- of this car's complaints
- 18%
- typical mileage
- 86,000
- crashes
- 2
- recalls
- 0
Which part fails
Owners did not name a specific part.
At what mileage
Complaints by mileage at the time of the problem.
0k-25k
25k-50k
50k-75k
75k-100k
100k-125k
125k-150k
150k-175k
175k-200k
200k+
Mercury Montego acceleration problems in other years
Specific symptoms reported on the 2005 Mercury Montego acceleration
Phrases found in the owners' own descriptions, so one complaint can mention several symptoms.
Related recalls
No recalls on record for this model year.
Related 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 (all vehicles are eligible for the program through May 31, 2013, regardless of mileage).Dealers will repair vehicles exhibiting the condition by removing and cleaning the throttle body and reprogramming the PCM with software containing an updated idle speed control strategy.According to Ford, some of the affected vehicles may experience momentary, intermittent engine idle RPM surge (idle flare) when stopped or during low speed driving maneuvers such as in a parking lot or driveway.Unstable idle speed control (dips and flares) around the target engine speed (700 rpm) can occur in vehicles with deposit build-up in the throttle body when the system adjusts engine speed in response to changes in engine load, typically from power steering application or air-conditioner compressor cycling.Idle speed control logic is only active at vehicle speeds below 3.5 mph and when the accelerator pedal is not applied.Ford testing of a vehicle with a worst case throttle body measured a maximum idle flare of 1360 RPM lasting approximately 1 second, which Ford indicated was consistent with system design to limit vehicle speed and acceleration in idle control mode.Ford indicated that the test vehicle was held in place with normal brake effort and that vehicle speed remained under 4 mph without the brake pedal applied.In addition to throttle body deposit accumulation, symptoms associated with the condition may include Check Engine lamp illumination and diagnostic trouble codes (DTCs) P0505, P0506 or P061B.Ford attributed the surge condition to changes in idle air flow resulting from the progressive buildup of deposits in the throttle body from normal Positive Crankcase Ventilation (PCV) system operation.This condition was not adequately compensated for in the original Powertrain Control Module (PCM) calibration.Ford issued a technical service bulletin on August 15, 2011 (TSB 11-8-5), releasing an updated powertrain control calibration for vehicles with CVT transmissions.On October 19, 2011, Ford issued a second bulletin (TSB 11-10-21) superseding TSB 11-8-5 and including updated powertrain control calibration for vehicles with 6-speed transmissions.Prior to Ford issuing the TSB?s, owner?s experiencing the alleged defect either received no repairs, if dealers could not duplicate the condition, or had the throttle body cleaned or replaced, which only provided temporary correction until the throttle deposit build-up returned.Ford?s revised powertrain calibrations appear to be effective remedies for the idle instability caused by build-up of throttle body deposits.However, even after the TSB?s were released, many owners experiencing the condition continued to have difficulty with proper diagnosis and repair as dealers were often either unable to duplicate the condition or were unfamiliar with the new repair procedures.Ford's new program addresses those concerns.the federal safety agency's testing and complaint analysis indicate that the idle speed control issue in the subject vehicles can only occur at very low speeds, are very brief events, are easily controlled by moderate brake pedal forces and result in minor increases in vehicle speed even with no braking.This investigation is closed.The closing of this in
PE11018
What 2005 Mercury Montego owners say
Most recent owner complaints, unedited.
The car has been lurching forward and decelerating randomly. Keeps going into "failsafe engine mode" and the wrench light comes on but only for a few moments, then runs normally again after restarting. Haven't been able to have the light on long enough to get diagnostics done. Happens while driving or when starting occasionally.
Sudden acceleration while in cruise control mode 65 or above. And will not stop unless brakes are applied to disengage the cruise control mode.
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 owns a 2005 mercury montego. While driving 15 MPH around a corner, the vehicle jerked and the check engine and fail safe mode warning lights illuminated. The vehicle was taken to the dealer where it was diagnosed that the throttle body control unit failed and needed to be replaced. The vehicle was repaired; however, the failure recurred. The manufacturer was notified of the failure. The failure mileage was approximately 150,000.
When braking it jerks and shifts into neutral and the engine reeves to 5000+ RPM. After braking and slowing it again shifts back into drive. This only happens when braking or increasing speed. No dash lights illuminate, indicating a problem. Having to slow suddenly in traffic is very dangerous. A ford dealer recommends a new transmission and a transmission shop recommends a new electronic module..this is an intermediate incident problem occurring approximately every two to four weeks. .
As I was entering onto the highway instead of accelerating the car decelerated and was losing power and RPM's went way too high then it should of. The transmission is not acting properly.the car has a clunking sound when hitting bumps.
As I was going down the highway, the car would suddenly feel as though I had put the gas pedal to the floor. It would suddenly accelerate even though I did not change the pressure on the gas pedal. I took the car to the local dealership and they had an owner notification from ford to clean the throttle body. The work was completed. However, the problem was never fixed. The vehicle would continue to do this on occasion. Now, the vehicle will completely shut off while I am driving down the highway. The fail safe light will come on and I have to coast to the side of the road. I have taken it back to the ford dealership and another $1,000 later I am having to replace the throttle body.
I was in the meddle lane of a four lane highway when I lost all my acceleration. The motor was still running but I could not go anywhere. When I got off the highway I restarted the car but every few miles it would do the same thing. Am told that it is a bad throttle body and ford has known about it for years but is not doing anything about it. It is going to get people killed ! My part cost over 600.00 so it sets in the drive.
Tl* the contact owns a 2005 mercury montego. The contact stated that while driving approximately 70 MPH and merging into the left lane, there was no response from the vehicle upon engaging the accelerator pedal. In addition, the vehicle jerked violently. The vehicle began to accelerate normally several seconds later. The vehicle was taken to an authorized dealer where the throttle body was being replaced. The manufacturer was not notified of the problem. The approximate failure mileage was 70,000.
Questions about the 2005 Mercury Montego acceleration
Does the 2005 Mercury Montego have acceleration problems?
Owners have filed 24 complaints about the acceleration of the 2005 Mercury Montego, 18% of all its complaints.
At what mileage do 2005 Mercury Montego acceleration problems start?
The typical (median) mileage in owner complaints is 86,000 miles.
Was there a recall on the 2005 Mercury Montego acceleration?
There is no recall for this problem on this model year.
What year does the Mercury Montego have the most acceleration problems?
The Mercury Montego model years with the most acceleration complaints are 2005 (24 complaints), 2006 (14 complaints) and 2007 (12 complaints).
Other 2005 Mercury Montego problems
Transmission 49Electrical 27Brakes 18Engine 17Fuel system 12Body 10Airbags 5Lights 3Locks 3Seat belts 2Visibility 2Wheels 2Driver assistance 1Steering 1Suspension 1Tires 1
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