It means your engine needs attention.
According to the 2005 Mercury Grand Marquis Owner Guide : ( 19.0 US. gallons )
In the 2005 Mercury Grand Marquis, the light control module is typically located behind the dashboard, near the steering column. It can be accessed by removing the lower dash panel on the driver's side. If you're troubleshooting or replacing it, ensure the vehicle's battery is disconnected for safety.
In the Gas Tank
owners manual.
on top of gas pedal
For a 2005 Mercury Grand Marquis : " regular " unleaded , 87 octane According to the Owner Guide
According to the 2005 Mercury Grand Marquis Owner Guide ( and one of Fords websites ) The ( Motorcraft FL-820-S engine oil filter is used )
Unbolt it from the floor.
Physically, yes. It would be best to consult an interchange reference to know if the wiring and programming are compatible.
The 2005 Mercury Grand Marquis , 4.6 liter SOHC , V8 engine has ( 2 ) timing chains ( 1 timing chain to each cylinder head )
Yes
No