Mercury Grand Marquis check engine light comes on

Filed Jul 17, 2025 · Acceleration, Brakes · 58,000 miles · PA

The contact owns a 2002 Mercury Grand Marquis. The contact stated while driving 50 MPH at night, the cruise control mode malfunctioned, and the speed of the vehicle increased independently. The contact stated that the brake pedal was depressed several times to the floor, but the vehicle failed to stop. The contact turned off the vehicle, and the vehicle came to a stop. The vehicle was towed to the contact's residence. The contact stated that he was afraid of driving the vehicle again. The contact unregistered the vehicle and turned the license plates of the vehicle to the Department of Motor Vehicles. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. Additionally, the contact stated that the check engine and the low oil pressure warning lights had illuminated two days prior to the failure. The manufacturer was made aware of the failure and a case was filed. The failure mileage was approximately 58,000.

Filed May 30, 2023 · Engine · 240,000 miles · NH

The contact owns a 2003 Mercury Grand Marquis. The contact stated while driving approximately 70 MPH, the vehicle started losing motive power. The contact stated that the vehicle had shifted to LIMP Mode and was almost side swiped by a tractor trailer. The contact stated that the check engine warning light was illuminated. The contact had not taken the vehicle to a local dealer. The vehicle had been towed to an independent mechanic; however, the vehicle was not diagnosed or repaired. The contact stated that the failure was intermittent at first but became a recurring failure. The manufacturer had not been informed of the failure. The failure mileage was approximately 240,000.

Filed Nov 29, 2021 · Engine · 150,000 miles · NC

The contact owns a 2004 Mercury Grand Marquis. The contact stated that she noticed a leak underneath her vehicle with the check engine and coolant warning lights illuminated. The contact had taken the vehicle to an independent mechanic where it was discovered that coolant had been leaking from a crack in the intake manifold. The dealer nor the manufacturer had been notified of the failure. The vehicle had yet to be repaired. The failure mileage was approximately 150,000.

Filed Jan 30, 2020 · Engine · 140,000 miles · ME

Tl* the contact owns a 2007 mercury grand marquis. The contact stated that when the vehicle was started, the check engine light illuminated and flashed. The vehicle was taken to an independent mechanic who diagnosed that the intake manifold fractured anti-freeze leaked into the oil. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was 140,000.

Filed May 28, 2019 · Acceleration, Engine · 118,000 miles · FL

Tl* the contact owns a 2000 mercury grand marquis. While driving various speeds, the vehicle hesitated to accelerate. The failure occurred most frequently when traveling up hill. The failure was intermittent and the check engine warning indicator illuminated. The dealer was not notified. The vehicle was not diagnosed or repaired. The contact sprayed carburetor fluid on the intake manifold and noticed a crack. The manufacturer was made aware of the failure. The failure mileage was 118,000.

Filed Jan 4, 2018 · Engine, Fuel system · 101,100 miles · FL

I was driving at a speed of 45mph on a county road in rush hour traffic when my car's engine light came on simultaneously as power of vehicle slowed while making a rattle type noise and cab smelled strongly of gas. I rolled windows down pulled over within a block to a napa store. The employee told me they do not run diagnostics and I would have to take it somewhere. I drove slowly to a 2nd auto parts store 1 mile away to run diagnostics. Once done, diagnostics identified a miss-fire on spark plug #2. Had vehicle towed to home and took 'heli-coil' off and spark plug came out with it damaged. The heli coil was also damaged. The threads of spark plug was flattened three threads from bottom. Contacted auto parts store again where the technician told me that ford has been having problems with there triton spark plugs blowing out on the 5.4l engines that they only screw in 3 threads into the head of the engine and there were pending lawsuits. The next day I called ford dealership and spoke with the acting service manager. "he told me there was nothing he could do about it and I should call customer care of ford: 800‑392‑3673. I did and rep. Told me there was no recall and my vehicle and it was out of warranty at 101,100.mi. There was nothing they could do. In the event there were to be a re-call to save my receipts and ford would reimburse me. I read about the problems that multiple customers were or had had regarding the same problem with a few vehicles leaking gas with the problem. This is all happening when the cars, trucks and suvs exceeds 100,000miles. I feel this is not only poor manufacturing of an inferior aluminum casing and spark plug and also not enough threads to hold the spark plug in safely. To have it jump out allows gas to also be expelled onto the cars remaining parts and vapors could ignite causing the car to potentially catch fire.

Filed Aug 1, 2017 · Engine · 110,000 miles · CA

The 1996-2001 mercury grand marquis with a 100% plastic intake manifold is known for engine overheating, even with normal use, and a coolant leak from the front of the manifold. This will often trigger the check engine light and low engine coolant warning light. The engine coolant leak is from a factory defect, which causes cracking on the front coolant passage of the intake manifold. In a very short time, this leak will lead to engine overheating issues, especially while the vehicle is idling. This is exactly what happened. I think the car part should have been replaced by ford when they new about the plastic intake manifold.

Filed Feb 10, 2016 · Engine · 178,000 miles · OH

Tl* the contact owns a 2003 mercury grand marquis. The contact stated that there was an abnormal noise coming from the engine and the check engine warning indicator illuminated. The vehicle was taken to an independent mechanic where it was diagnosed that the number two cylinder spark plug misfired and the head of the motor needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 178,000.

Filed Sep 17, 2015 · Acceleration, Engine · 136,037 miles · FL

Tl* the contact owns a 2001 mercury grand marquis. The contact stated that while driving at approximately 70 MPH, the vehicle was jerking and the ABS and the check engine warning lights illuminated. The vehicle had a drastic reduction in speed. The vehicle was restarted. The vehicle was taken to the dealer on several occasions where it was repaired but the repair details were unknown. The repairs failed to remedy the vehicle. The contact stated the service engine warning light continued to illuminated and the vehicle jerked violently, reduced speed and attempted to stall. The manufacturer was notified of the failure. The approximate failure mileage was 136,037. Updated 12/03/15

Filed Nov 11, 2012 · Electrical, Engine · 106,243 miles · CA

The car all of a sudden felt different while driving one day, kind of sluggish and then the engine light went on. The temp rose and smoke started coming out from under the hood. When I pulled over to let cool down I couldn't start it up again. Had it towed to a mechanic who said that the engine was shot. Not worth repairing. Had it towed back home and its been parked in my driveway ever since.