Three problems related to automatic transmission have been reported for the 2003 Mercury Grand Marquis. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Mercury Grand Marquis based on all problems reported for the 2003 Grand Marquis.
Automatic transmission shifts erratically when in cruise mode, less than 70,000 miles on vehicle, has almost caused accident several times. Have to dis-engage cruise control and shut off overdrive to cure it, and keeps occurring although less frequently.
The vehicle's shifter jumped out of park and into reverse. As a resulted the vehicle rolled backwards and was involved in a minor collision.
When the consumer put the gear into reverse on an incline, the vehicle continued to move forward. Ph.