2008 Mercury Mariner: adaptive cruise control problems

Filed Jun 15, 2017 · Acceleration, Engine · 101,851 miles · AZ

The throttle is held open when the cruise control is employed but remains open when the cruise control is turned off both by using the off button and brake application. This happens at 75-80 MPH on interstate highways in az and ut. The power brake booster is ineffective with no intake vacuum. This is very dangerous.

Filed Apr 21, 2017 · Acceleration, Steering · 135,000 miles · TN

Tl* the contact owns a 2008 mercury mariner. The contact stated that while driving at various speeds, the cruise control malfunctioned as well as the rpms. The contact stated that the rpms were inconsistent with the actual speed of the vehicle and went up to 4000 rpms at various speeds. In addition, there was a loud clunking noise in the steering wheel and the contact stated that the vehicle downshifted on numerous occasions. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was 135,000.

Filed Jan 1, 2017 · Acceleration, Fuel system · 72,300 miles · ND

My wife and I were driving home on the interstate. We had just merged to the passing lane to allow traffic merging from an on ramp to enter the interstate a vehicle next to us was doing the exact speed as we were which was 72 MPH set cruise control. I had vehicles approaching from the rear and since I was in the passing lane decided to speed up and get in front of the car beside us I pushed the accelerator on our 08 mercury mariner with a 3.0l engine to the floor and the car accelerated in front of the other car, when I lifted my foot off the accelerator the car continued to accelerate. I pushed on the brake once with nothing changing the car continued to accelerate. I proceeded to pump the brake three additional times in about 1 second intervals. Finally the accelerator pedal release and the car slowed down. We preceded home without further incident. This is a very dangerous condition and has resulted in serious injuries and deaths in earlier model years of ford escape, mercury mariner and mazda tribute vehicles. I have had ford vehicles my whole life and have been working on vehicles for more than thirty five years. This is not normal and is not the only time or vehicle this has happened to in this year there are many other similar people that have similar complaints on these ford and mercury SUV's on the internet ex: carcomplaints.com to name just one. The internet is filled with these dangerous complaints. When are you going to live up to your name and put the safety aspect first,when dealing with these to rich to be bothered by recalls auto manufacturers?

Filed Jun 24, 2010 · Acceleration, Brakes · 56,000 miles · OR

In december of 2009 I reported an incidence of unintended acceleration. Since then we have not been using the cruise control much. Yesterday I activated the cruise control at 60mph on a long flat area. There is a mountain pass and curves between that area and our home. I hit the brake and slowed down around the 35 MPH curves. On the down grade I took it out of over drive and dropped down a gear. The road flattens out again at the bottom but I did not reengage the cruise control. At one point at an intersection I had to brake to ten miles per hour or less for an oncoming car. Just after making a left turn onto our street the car began rapidly accelerating on its own. I didn't have my foot on the gas pedal. Since the road is straight I allowed it to accelerate to see what it would do. It went from 10 MPH to 50 MPH before my wife asked, "why are you accelerating? I replied, " I'm not. It's doing it on its own." it disengaged as soon as I hit the brake pedal. There is no way this was caused by a floor mat. I was only going about 10mph when it began accelerating and I took my foot off the pedal. The last time I complained to ford the car was under warranty and had less than 36,000 miles on it. Ford said they couldn't do anything about it since it was intermittent and they hadn't experienced the problem. Another safety problem we have had with the car: when it had 26,000 miles on it the front end began shaking when braking. Ford said the front rotors were warped and resurfaced them under the warranty. They refused to change the pads or install new rotors. About 15,000 miles later it began vibrating again at speeds above 50mph. Now the vibration is severe. We are looking at a complete brake overhaul. We have never detected the brakes being overheated while the car was being driven. Another problem we had was that the trans cooler went out at 26,000 miles. Ford installed a new one under warranty but refused to drain and replace the transmission fluid.

Filed Dec 8, 2009 · Acceleration · 41,201 miles · OR

Unintended acceleration. Ascending a winding grade on oregon 140 at 50 MPH the accelerator pedal suddenly shot unaided to the floor putting the car in passing gear. When I hit the brake pedal it instantly disengaged the accelerator. The car was not in cruise control mode although it had been earlier. I had disengaged the overdrive function through the button on the gear shift lever and was in straight drive gear. We bought the car in january 2009. This was the 3rd time we have experienced this same problem. This time was the most pronounced and serious since the accelerator was floored. We were passing over the cascades between medford and klamath falls. Two or three miles further up the highway we entered the snow zone and there was ice on the highway. Had we been there at the time of the sudden acceleration the car could have spun out of control.

Filed Oct 18, 2009 · Acceleration · 15,682 miles · VT

On 09-24-2009 while traveling on I-95 towards maine near portsmouth, new hampshire, our vehicle a 2008 mercury mariner, with 15,682 miles on the odometer, lost all braking capability at 65 MPH. Being a retired police officer I was able to talk my wife, who was driving, over into a breakdown lane in an effort to avoid collision with tractor trailers, motor vehicles and fixed objects. Ultimately the vehicle was turned onto an off ramp and onto a sidewalk and grass area to increase friction to reduce speed. This was several miles in the making and when the vehicle slowed to under 40 MPH we placed it in neutral and were able to stop the car. We noted that the rpms were in the 4,000 to 5,000 range as the throttle appeared stuck. After towing to portsmouth ford, in portsmouth, new hampshire; technicians there determined that the problem was a stretched throttle control & cable assembly (part #7l8z*9!758*c cable ass-throttle contro and part # 8l*z*9725*a shaft mt79758a-accelerator cable). Techicians stated that the stretch accelerator cable (which they said was poorly designed) caused the throttle and cruise control to lock, which over rode the braking system. Warranty repairs were made invoice 497086 tag customer #8023451243. We narrowly avoided what could have been a catastrophic accident and feel this should be brought to your attention as a defect may exist in other simllar 2008 mercury mariners.