One problem related to engine exhaust system has 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.
Stainless steel exhaust was rusted. The vehicle had a stainless steel exhaust. After the return from florida where they stayed for winter, the exhaust system was found rusted.