they are located under the coil pack
Exhaust system.
O2 sensors are always located on the exhaust system.O2 sensors are always located on the exhaust system.
It is located in the Y pipe of the exhaust.
There are 2 sensors. One in front of the catalytic converter and one behind it.
Bank 2 is the drivers side of the engine on your 1999 Mercury Marquis Sensor 1 is before the catalytic converter ( upstream ) Sensor 2 is after the catalytic converter ( downstream )
AnswerThere are three O2 Sensors on my 1999 Cougar. Two are located just before the Y-Pipe and are both wired to the drivers side of the Y-Pipe. The other is located just after the Catalyic Converter.Easy to change.
They are located internally in the transmission itself.
The O2 sensors are screwed into the exhaust system. Follow the exhaust backward from the engine and you will find the sensors.
The 1999 Mercury Grand Marquis air suspension relay switch can be found on the firewall in the engine compartment. The air suspension relay switch will be on the passenger side of the firewall.
If it could they wouldn't be on there in the first place. Truthfully, it'll run BETTER with them, if you take them off, your gas mileage will suffer.
The O2 sensors are located between the exhaust manifolds and the cat converter. They screw in to the head pipes. Those are also called upstream O2 sensors and in some vehicles they are also called air/fuel sensors. There are also downstream O2 sensors that are located after the catalytic converter.