Oxygen Sensors I would like to find out if you could provide a layout of the engine for a Mercury Sable. I need to repair the Oxygen Sensors on my Mercury Sable to be exact bank 2 and sensor 2. So I would like to find out if you could assist me with a diagram so I know where the Oxygen Sensors are on my Mercury Sable 2001

22mm wrench & unscrew it

Get under the car,look for the converter
& remove the sensor

I guess you don't use the internet much, to
research things, or actually work on vehicles

Now instead of wasting time with checking for codes,
actually have a shop diagnose the issue

When you ask for help with your vehicle, I personally recommend that you mention WHICH 3.oL engine your vehicle is equipped with. I know that you probably did not know that there is two different ones. There is a 3.0L Dual Over-Head Cam (DOHC) engine (VIN Code "S"), and there is a 3.0L Over-Head Valve (OHV) engine (VIN Code "U").
Both of these engines are notorious for Mass Air Flow (MAF) sensors and vacuum leaks, however, these problems will cause problems on BOTH banks, not just one. You most likely have a "lazy" oxygen sensor. It just isn't switching like it should. The best way to diagnose this condition is to get the car on a scanner that can read sensor data and look to see what the downstream oxygen sensors are doing. If you have a lean code for the upstream sensor and you have high voltage readings (RICH or above 600 millivolts) on the downstream sensor, then the engine is not really running lean - the upstream sensor is lying and needs to be replaced.

Since you are getting a lean oxygen sensor code and it is using a lot of gas, I would say that this is most likely the case. An oxygen sensor that is lying to the computer about the system being lean will cause the computer to open the injectors wide open. Take a look at your tailpipe and see if it is really black. A normal exhaust pipe will look light tan in color. If the tail pipe is black, this is a really good indication that the system is actually running rich and the oxygen sensor is lying about it.

Your vehicle has four oxygen sensors. There is a vacuum line underneath the throttle body that regularly fails, causing the lean condition, and the whistling and surging. Very dificult to see, but with the engine running usually you can fine the vacuum leak with your fingers. Hose is non-reinforced rubber, and is shaped in a 90 degree bend. If memory serves me right, it is the pcv hose. Replace this and your problems will cease.

ford say 100.000 miles is about the time for a tune up it would also not be a bad idea to change all oxygen sensors at this time even if there still working.

Two are in each exhaust pipe near the connection to the header and two are at the outlet of each catalytic converter. Upstream and downstream.

they just unscrew from the exhaust pipe.

Heated Oxygen Sensor (HO2S) SPECIAL SERVICE TOOL(S) REQUIRED Description Tool Number Oxygen Sensor Wrench T94P-9472-A
Removal and Installation

1. Disconnect battery ground cable (14301). Refer to Section 14-01 .
   

1. On 3.0L (4V) engine remove cowl extension and right side of leaf screen.
   

1. Disconnect engine control sensor wiring (12A581) from heated oxygen sensors (HO2S) (9F472). Do not remove harness connectors from the brackets.
   

1. Raise vehicle on hoist. Refer to Section 00-02 .
   

1. NOTE: If excessive force is needed to remove a heated oxygen sensor, lubricate the heated oxygen sensor with penetrating oil prior to removal.
   
   Remove heated oxygen sensors from exhaust manifolds (9430) using Oxygen Sensor Wrench T94P-9472-A.
   

1. To install, reverse Removal procedure. Apply a coating of anti-sieze compound to threads of heated oxygen sensor. Tighten heated oxygen sensors to 34-46 Nm (26-34 lb-ft).
   
   
   Heated Oxygen Sensors—3.0L (4V) Engine
   
   
   

you have 2 ox sensors on that one before the cadalitic converter and one after it!!
first i would give it a complete tune up and change the fuel filter !!!!!!

one it is near catalyst converter in the front under engine.