There are four oxygen sensors screwed into the converter assemblies. You need to know which one is faulty before attempting to replace them.
The 2003 Mercury Grand Marquis came equipped with the 4. 6L V8. Oxygen (O2) sensor locations are upstream and downstream (before and after the catalytic converters).
On a 1998 Mercury Grand Marquis : Bank 2 is the drivers side of the engine Sensor 1 would be in the exhaust close to the engine before the exhaust enters the catalytic converter ( upstream sensor )
How do you replace the timing chain on a 1994 mercury grand marquis
how do i replace a passenger side headlamp for a 2004 grand marquis gs
there one on right-its on the side after the cat there's one on the headers right lower side
How many o 2 sensors on a 2001 grand marquis
I've had a similar problem with my 92 grand marquis. I had to change the mass air flow sensor and replace a broken vacuum line. after that my car ran better than it ever did.
Location of coolant temperature sensor on a 2003 Mercury Grand Marquis?Read more: Location_of_coolant_temperature_sensor_on_a_2003_Mercury_Grand_Marquis
how do you replace the front sway bar likn in a 1999 Grand Marquis?
how to replace starter on 2000 mercury grand marquis
anywhere from 30 - 75 dollars
how do you get to and replace the wiper moter on a 97 marquis