Which parts fail
Components named in complaints (accelerator pedal, throttle, sudden acceleration, cruise control).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2006 Mercury Grand Marquis owners, lightly cleaned up (personal details are redacted by NHTSA).
Tl* the contact owned a 2006 Mercury Grand Marquis. While driving at an unknown speed with the cruise control activated, the vehicle suddenly accelerated. The rear brakes locked when the failure occurred. The contact was unable to stop the vehicle and crashed into a tree. The air bags failed to deploy. The front seat passenger was injured and received medical attention. The vehicle was destroyed. A police report was filed. The VIN was not available. The failure mileage was 38,000.
Tl* the contact owns a 2006 Mercury Grand Marquis. While driving into a parking space at approximately 5 MPH, the brake pedal was depressed and the vehicle unintendedly accelerated and crashed into the side of a concrete building. There were no injuries and a police report was filed. The vehicle was towed to an independent mechanic where the front end damages were repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 45,800.
I had an incident of unintended acceleration on my Mercury Marquis. I was braking for a stop when the engine suddenly started racing. I put my foot on the brake hard but the car still continued to move slowly until I hit the car in front of me. There was no damage to either vehicle (fortunately) but the car's engine was completely out of control.
Tl* the contact owns a 2006 Mercury Grand Marquis. The contact was attempting a left turn when the vehicle suddenly accelerated and crashed into the side of a building. No one was injured. The vehicle was damaged at the hood and the grill. The police were contacted and an incident report was filed. The contact stated that the vehicle abnormally accelerated on another occasion which also resulted in a crash. As the contact shifted into drive, the vehicle lunged forward and the RPM's increased excessively. The vehicle crashed into a parked vehicle but no one was injured. A police report was also filed of the second incident. The contact stated that both of the incidents that LED to a crash occurred immediately after utilizing the cruise control function. The contact stated that he was planning to have the feature removed from the vehicle. The manufacturer was not notified of the failure. …
Dt*: the contact stated there were three separate problems with the vehicle. The first problem occurred when the automatic pedal adjuster was being used the engine revved. The second occurred while driving, the accelerator pedal was difficult to depress, after several miles of driving in this condition, the contact pressed and released the pedal and it suddenly resumed normal operation. While in stop and go traffic driving at 20 MPH the vehicle surged forward, while the brakes were applied and rear ended another vehicle. Seatbelts were in use; no injuries were sustained to the four occupants of the contacts vehicle, however the driver of the other vehicle sustained injuries. The police were on scene but no report was filed. The vehicle was returned to the rental agency and another model was issued.
Tl contact owns a 2006 Mercury Grand Marquis. While driving at approximately 30 MPH, the vehicle suddenly accelerated up to 50 MPH although the contact depressed the brake pedal. The vehicle would not slow down even after the contact turned off the ignition and continued to coast up the hill until it crashed into a curb. There were no injuries but a police report was taken. The vehicle was towed to a local repair shop where it was repaired. After the repair, the dealer performed a diagnostic test on the vehicle but no failure was found. The contact called the manufacturer and was told that they would get back with him for an investigation. The current and failure mileages were 30,351.
Tl* the contact owns a 2006 Mercury Grand Marquis. While driving 45 MPH, the vehicle accelerated independently. The contact depressed the brake pedal, but the vehicle did not stop. The contact was able to place the vehicle in neutral and depress the brake pedal in order to stop the vehicle. The vehicle was not taken to be diagnosed or repaired. The failure was intermittent. The dealer was not contacted. The manufacturer was notified of the failure. The approximate failure mileage was 170,000.
Stopped at railroad crossing. Train moving. 1 car ahead of me at railroad. Stop. I was completely stopped. After being stopped for about a minute my car suddenly accelerate and slammed into car in front of me pushing car forward in the side of moving train. My car also slammed into train and was reversed and stopped on railroad post. During this time I could not stop vehicle. The vehicle was traveling at considerable speed.
The vehicle accelerated on it's own while stopped with the brake depressed. Once in a parking lot waiting for a spot to clear.the second time while sitting at a red light. I held the brake down as hard as I could while the car did a burn out and I noticed the traction light come on. It then just went back to normal. This is very dangerous. Someone in front of the car (another driver or pedestrian) can seriously get hurt or killed.
As I was driving. 35mph my front wheel on the driver side had snapped off causing my vehicle to crash into a parked vehicle. Long story short. I'm going thru a financial crisis. My car was towed by aaa to my house. I notified my insurance company. Why did the police tow my car away from my house? Somebody needs to take care of this because I can't. Transportation is essential to me. Please I need help.
Acceleration complaints in other Grand Marquis years
Frequently asked questions
How common are acceleration problems on the 2006 Mercury Grand Marquis?
NHTSA has 37 complaints about the speed control & acceleration of the 2006 Mercury Grand Marquis, 26% of the model year's 143 complaints. The component named most often is accelerator pedal (2 mentions).
Is there a recall for 2006 Mercury Grand Marquis acceleration problems?
No. NHTSA lists no speed control & acceleration recall for the 2006 Mercury Grand Marquis, though it has 2 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2006 Mercury Grand Marquis acceleration problems start?
Half of the complaints with a recorded mileage happened before about 38,000 miles, and 29% before 25,000 miles.
Is it dangerous?
Owners linked 8 crashes, 1 fire and 5 injuries to speed control & acceleration problems on this model year. If you notice symptoms, have the car checked before driving further.
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.