NHTSA — Vehicle Speed Control Problems


really awful
Crashes / Fires:
7 / 1
Injuries / Deaths:
5 / 0
Average Mileage:
37,569 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2006 Mercury Grand Marquis engine problems

engine problem

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2006 Mercury Grand Marquis Owner Comments (Page 1 of 2)

problem #32

Aug 192016

Grand Marquis

  • 66,000 miles


Cruise control will not work nor power on. Cigarette lighter outlet has no power.

- Oak Ridge, TN, USA

problem #31

Apr 052016

Grand Marquis

  • 45,800 miles
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.

- Walnut Ridge, AR, USA

problem #30

Jan 252016

Grand Marquis

  • miles
The contact owns a 2006 Mercury Grand Marquis. The contact stated that while driving at various speeds, the vehicle accelerated independently without warning. The vehicle was taken to an independent mechanic but the failure was unable to be determined. The manufacturer was not notified of the failure. The failure mileage was unknown.

- Lake City, FL, USA

problem #29

Aug 172015

Grand Marquis

  • 58,300 miles


The contact owns a 2006 Mercury Grand Marquis. The contact stated that while driving at 10 mph attempting to engage the brakes, the vehicle suddenly accelerated without warning. The failure recurred three times. The vehicle was taken to a dealer but was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was 58,300.

- Portage , WI, USA

problem #28

Apr 082010

Grand Marquis

  • 38,000 miles
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.

- Leesburg, FL, USA

problem #27

Feb 092015

Grand Marquis

  • 215,000 miles
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.

- New Orleans, LA, USA

problem #26

Oct 012014

Grand Marquis 8-cyl

  • 117,500 miles


Driving at 50 mph. Passed slower-moving vehicle by pushing accelerator to floor(full power) during initial pass, then released accelerator. Engine RPM's did not reduce, but instead climbed rapidly with the throttle stuck at the "full power" position. The vehicle continued to accelerate rapidly, reaching a speed of about 75 mph in 50 mph zone on two lane road. Upon recognizing the accelerator was stuck in "wide open" position, I slammed my foot against the accelerator pedal repeatedly, and after about three strikes the engine RPM reduced to normal (consistent with accelerator pedal position) and I was able to regain control of the speed and slow the vehicle. I checked to ensure that neither the floor mat nor any foreign objects were impinging on accelerator pedal. I found no objects interfering with the accelerator pedal. This same problem occurred two more times within two weeks. I reported the events to my local mechanic and he ran a computer diagnostic on the system. It showed no abnormalities or codes. Two mechanics examined the system under the hood and noted no abnormalities. They indicated they "cleaned" something (contacts?). I subsequently took the vehicle onto a larger road without traffic present and attempted to duplicate the problem. When I pressed the accelerator to the floor (full throttle), the same problem occurred. The engine RPM continued to climb rapidly and the vehicle accelerated uncontrollably and rapidly. Taking my foot off the accelerator resulted in absolutely no reduction to engine power. Engine RPM and speed rapidly increased as the engine was stuck in the "full power" position. I was only able to regain control of the engine speed and vehicle speed by repeatedly slamming my foot against the accelerator pedal. After two or three hits, engine power reduced consistent with accelerator position.

- Blue Hill, ME, USA

problem #25

Jun 022014

Grand Marquis

  • miles
The contact owns a 2006 Mercury Grand Marquis. While approaching a traffic light, the vehicle accelerated when the brake pedal was depressed. The contact had to apply the brake pedal and shift into neutral in order to stop the vehicle. An independent mechanic was unable to diagnose the failure, but replaced the throttle position sensor and throttle body. The manufacturer was not notified. The failure mileage was unavailable. Updated 12/03/14

- Orland Park, IL, USA

problem #24

Sep 212014

Grand Marquis

  • 102,000 miles
Upon readying for stop the vehicle surged forward. I had to put in neutral and wait until the surge discontinued. This has been going on for several months. It has become a incident that happens more often. It is very scary. A had jump happens when I put it back in gear.

- Huntsville, AL, USA

problem #23

Jun 012014

Grand Marquis 8-cyl

  • 62,800 miles
On 6/1/14 I was driving South on SR44 in Ohio near lake punderson and following a farmer driving a farm tractor.when I got a chance to pass him I accelerated to kick in the passing gear and when I cleared him and left off the throttle it did not respond instead it continued at a high speed for a few seconds before letting off.I thought maybe the throttle got caught on my car mat. I very rarely push the throttle to the floor. Then yesterday 8/20/14 I was with my family traveling North on I-77 in akron Ohio and again I kicked the car into passing gear to pass and this time it accelerated and did not retract on my letting off. I slid the shifter into neutral and placed my foot under the pedal and lifted up and it came up but I thought I felt some resistance with the peddle.I continued on to my destination only a few miles to copley Ohio.I parked the car turning off the engine and slid the seat back and on my knees in the driveway I reached in with my right hand and pushed the peddle all the way in and let go of it and to my surprise it remained in the full throttle position. I then pulled the throttle back and felt resistance. I pushed it back in again and it stuck but came back with less resistance so I pumped it back and forth and got rid of the sticking problem.I then thought it may of developed some light rust on the linkage so I looked up under the dash and there is no place to lubricate that's when I realized I really had a problem and possibly a lot of people owning a similar car.as of this writing I went out to the car in the garage and reached in and pushed the throttle to the floor and it came back nicely.a lot of people will not react as I did and shift into neutral.

- Ravenna, OH, USA

problem #22

Mar 022014

Grand Marquis

  • miles


The contact owns a 2006 Mercury Grand Marquis. The contact stated while driving 40 mph, an unknown warning light illuminated on the instrument panel then the vehicle stalled. The vehicle was taken to an independent mechanic who stated that the throttle body system needed to be replaced. Shortly after the repair, the vehicle caught fire and was destroyed. The manufacturer was made aware of the failure. The failure and the current mileages were unknown.

- Greenville, MS, USA

problem #21

Nov 042013

Grand Marquis 8-cyl

  • 55,000 miles
On several occasions since I've owned this vehicle (I am original owner) when I step on the brakes hard the engine accelerates. Recently it has gotten worse and I know I'm not touching the accelerator. Today it was so bad the I was standing on the brakes with both feet and burning rubber. I shifted to park and the engine went onto max acceleration. I shut of the engine and restated and found it was still at max acceleration. I shut it off again and waited 30 seconds. When I then restarted it ran normally. Fortunately I was at a stop sign or I think there would have been a collision if in traffic.

- South St Paul, MN, USA

problem #20

Nov 042013

Grand Marquis 8-cyl

  • 52,000 miles
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.

- Miami, FL, USA

problem #19

Jul 292013

Grand Marquis 8-cyl

  • 29,802 miles
Over the course of several months the engine seemed to rev up while the brakes were applied for a stop. On July 29,2013 I took the car to a reliable service center and asked for an analysis of what the cause could be. Analysis result indicated that the throttle body assembly was the problem. A new assembly was installed, and I was informed that Ford has a bulletin on that particular part on 2006 Grand Marquis. The mechanic felt that a recall should be issued for safety reasons.

- Louisville, KY, USA

problem #18

Jul 172013

Grand Marquis 8-cyl

  • 22,538 miles
I was driving up to a light and slowing down. When at 25mph the car suddenly accelerated and I had to put all my weight on the brake to stop. After about 10 seconds the car went back to normal and ran fine. Since that incident my car has done that twice with the same result and I am worried someone will get hurt. I have been researching this online and have found other complaints. I will be taking the car to my mechanic asap.

- Hampton, NJ, USA

problem #17

Mar 292012

Grand Marquis

  • 33,000 miles
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. The failure mileage was 33,000 and the current mileage was 45,400.

- North Babylon, NY, USA

problem #16

Mar 132006

Grand Marquis

  • 2,000 miles
The contact owns a 2006 Mercury Grand Marquis. The contact stated that while stopped at a stop light, there was an increase in the engine rpms. The contatc had to apply heavy pressure to the accelerator pedal to keep the vehicle stopped. The failure occurred intermittently and the vehicle also experience unintended acceleration. The vehicle was taken to the dealer, who inspected it and stated that there was no failure. The manufacturer was not notified. The failure mileage was 2,000 and the current mileage was 111,000. The VIN was unknown.

- Glendale Heights, IL, USA

problem #15

Jul 182010

Grand Marquis

  • 28,000 miles
The contact owns a 2006 Mercury Grand Marquis. The contact stated the vehicle surged forward on three separate occasions while the brakes were engaged. During two of the failures the contact applied excessive pressure to the brake pedal to stop the vehicle. On one occasion the vehicle stopped accelerating on its own.the vehicle was taken to a repair shop but the mechanic was unable to diagnose the failure. The vehicle was not repaired. The manufacturer was made aware of the failure and the contact was advised to take the vehicle to an authorized dealer. The failure mileage was 28,000 and the current mileage was 32,800.

- Flagler Beach, FL, USA

problem #14

Mar 212011

Grand Marquis

  • 73,250 miles
I am certified safety professional with over 30 years experience working in the occupational safety field. Twice within the last week, my vehicle accelerated to 5000 RPM while pressing the brake pedal to stop at an intersection. My foot was on the brake pedal and not on the gas pedal. I had to quickly shift into neutral to avoid entering the intersection into crossing traffic. Brakes would not hold. A few seconds after shifting into neutral the engine decelerated back to normal on its own. Carpet was not the issue. This is a serious malfunction that could have killed me or someone else.

- Medina, NY, USA

problem #13

Dec 282009

Grand Marquis

  • 16,400 miles
Car acceleration on its own, estimated start end of Dec.2009. Estimates that it happens once a month, no clue as to when it will happen. Going to slow down / park, car starts to accelerate on its' own., have to press hard on brake and use 2 feet.. brought car into dealer 4 times between Jan thru June, at this point. Dealer says can't find anything.

- Naples, FL, USA

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