One problem related to manifold/header/muffler/tail pipe 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.
Intake manifold cracked and leaked coolant onto the coils and spark plugs. Hence causing rough running engine and lack of performance.
| Engine problems | |
| Engine Cooling System problems | |
| Car Stall problems | |
| Engine Belts And Pulleys problems | |
| Engine Exhaust System problems | |
| Loud Engine Noise problems | |
| Engine Rattling And Whining Sounds problems | |
| Manifold/header/muffler/tail Pipe problems |