On a 1996 Grand Marquis there are 4 oxygen sensors. 2 (1 on each bank) are mounted before the front catalysts near the manifold-->cat-pipe flange. These are the HEGOS or Heated Exhaust Gas Oxygen Sensor. These are the primary o2s and are what help the PCM determine the correct A/F ratio. There are another 2 directly after the fisrt set (1 on each bank) of catalysts moutned on the exhaust piping between the two catalysts on each bank. The primary goal of these is to monitor the catalysts' effieceincy. In summary: 4 o2 sensors in all 2 are the upstream/HEGOS o2s 2 the downstream o2s 4 cat-convertors in all
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 )
Location of coolant temperature sensor on a 2003 Mercury Grand Marquis?Read more: Location_of_coolant_temperature_sensor_on_a_2003_Mercury_Grand_Marquis
on the transmission
firewall 4 - 8 3 - 7 2 - 6 1 - 5 front of Mercury Grand Marquis
Bank 2 is the drivers side of your engine , Sensor 1 is in the exhaust before the catalytic converter ( upstream )
Mercury Grand Marquis was created in 1983.
next to the crank pulley
On a 1999 Mercury Grand Marquis : The Mass Air Flow Sensor should be between the engine air filter and the big engine air intake tube
On a 1996 Mercury Grand Marquis , 4.6 liter V8 engine : Bank 1 is the passenger side of the engine Sensor 2 would be AFTER the exhaust has passed through the catalytic converter
On a 1997 Mercury Grand Marquis : Bank 2 is the drivers side of the engine and ------------------------------------------------------------------------------------------ Sensor 1 would be close to the engine before the exhaust enters the catalytic converter Sensor 2 would be AFTER the exhaust has passed through the catalytic converter ( also called a catalyst monitor )
Bank 1 is the passenger side of the engine in a Mercury Grand Marquis Sensor 1 would be in the exhaust close to the engine before the exhaust enters the catalytic converter ( upstream sensor )