There are 5 owner-reported brakes complaints for the 2004 Mercury Grand Marquisin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
TL* THE CONTACT OWNS A 2004 MERCURY GRAND MARQUIS. THE CONTACT STATED THAT WHILE DRIVING AT APPROXIMATELY 5 MPH AND DEPRESSING THE BRAKE PEDAL, THE VEHICLE ACCELERATED. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOT NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 162,000.
TL* THE CONTACT OWNS A 2004 MERCURY GRAND MARQUIS. WHILE DRIVING 8 MPH THE VEHICLE DID NOT STOP WHEN THE BRAKE WAS DEPRESSED. HE STATED THAT IT WAS APPROXIMATELY 30 SECONDS BEFORE THE VEHICLE STOPPED. THE ROAD CONDITIONS WERE CLEAR. THE VEHICLE WAS NEVER INSPECTED. APPROXIMATELY FOUR DAYS LATER THE CONTACT EXPERIENCED THE SAME PROBLEM. HE STATED THAT HIS VEHICLE CRASHED INTO A WOODEN POLE. THE VEHICLE WAS TOWED TO A MECHANIC TO REPAIR THE DAMAGE AS A RESULT OF THE CRASH. THE MECHANIC WAS UNABLE TO DIAGNOSE THE FAILURE. THE CURRENT MILEAGE WAS 36,000. *AK
WHEN PRESSING BRAKE PEDAL, FOOT ALSO FREQUENTLY DEPRESSES GAS PEDAL CAUSING CAR TO LURCH FORWARD. *JB
THE ADJUSTABLE PEDAL CAN GO BACK OR FORTH WHEN HITTING THE BRAKE PEDAL THE GAS PEDAL IS SO CLOSE THEY HIT TOGETHER.*AK
WHEN ATTEMPTING TO PRESS THE BRAKE PEDAL, THE DRIVER ALSO PRESSED ON THE ACCELERATOR PEDAL AND CAUSED THE VEHICLE TO ACCELERATE WHICH MADE IT DIFFICULT TO STOP THE VEHICLE. THE CONSUMER STATED THAT THE PEDALS WERE TOO CLOSE TO EACH OTHER. *AK *SC *JB
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 26, 2026