Jack the car up and crawl underneath
Use proper safety stands!!
You must remove the fuel tank in order to access the fuel pump.
Our 1988 Mercury Cougar with the 3.8 liter V-6 dropped drastically in mileage to an average of 10.5 mpg. I checked one of the oxygen sensors, located in the exhaust manifold, and it was filthy so I cleaned it with carburetor cleaner. Our mileage shot up to 18 mpg and the car is running better. I haven't gotten to the other oxygen sensor because it is in a difficult to reach place. I will be replacing both of them in the near future.
The Vehicle Speed Sensor on the 1996 Mercury Villager is located on the back of the transmission (as you look at the vehicle from the front) on top of the transmission with a pair of wires leading away from it... best to reach it from under the vehicle.
Follow the transmission pan up and around front corner. It will curve upward slightly. Reach over this ear and you will feel the sensor wire.
On a 3.3 or 3.8 you may have to remove the wiper cowling to access.
The passenger compartment fuse panel on a 2002 Mercury Cougar is located underneath the dashboard on the driver's side. To access it, you may need to remove a cover or panel, which is typically held in place by clips or screws. Consult the owner's manual for specific details on the location and any additional steps needed to reach the fuse panel.
On a 1999 Mercury Marquis, bank 2 sensor 2 is located on the exhaust system after the catalytic converter on the driver's side of the vehicle. This sensor monitors the exhaust gases to help manage emissions and fuel efficiency. To access it, you may need to lift the vehicle for better visibility and reach.
The Oxygen Sensor on a 1989 Cherokee 4.0L is on the exhaust pipe on the left side of the engine just below the exhaust manifold. You can see it from above but you must replace it from below. It is pretty easy to reach. I recently changed mine and it took only 10 minutes using an O2 sensor wrench.
Well, this just happened with my car and what I have to get done with it means that half the motor needs to come out to get to it. Well, for half of the motor to come out you have to take out the whole thing. Once you do that you can then reach the bolt and I'm sure you know where to go from there. but your gonna have to drop the motor to reach it.
The Oxygen Sensor or O2 senser, as it is sometimes called, is screwed into the exhaust manifold close to where it joins the exhaust pipe. You must jack the car or put it on a rack and get to it from under the car. If you are replacing it yourself you will need a crow's foot wrench.
Neptune can reach way below freezing and Mercury can reach way above burning.
the oxygen sensor is on the exhaust system located straight down from the firewall in the middle of the engine compartment you need a special socket tool like a line wrench because you have to go around the two wires that leads into the sensor, you also need long extension to reach the area, like a foot an a half extension with your ratchet.