I am changing an o2 sensor on my 1997 nissan pathfinder. Where is the plug located? (it's the driver side rear oxygen senor)

The O2 sensor with a heater is after the cat, called Bank 2. The first one, nearest the engine, is not heated, Bank 1.

There is 4 senors the bank 1 sensor 1 is located in front of the LH (Drivers side) catalytic converter
Hope this helps

Hi James,here's a link to your firing order,cylinder two is bank two and sensor one is the oxygen sensor screwed into the exhaust manifold on that side.

O2 sensor ? You should change them in pairs. Bank 1 is on driver side.

It sounds like you have a faulty TPS (throttle position sensor) sensor, it is an easy fix, and you can get the part from any auto parts store. The TPS sensor is located on the throttle body, and it is held in place with 2 screws and has 1 plug to it. Before you change it, make sure that it is plugged in. Mine did the same thing and somehow the TPS had came unplugged, so I plugged it back in and the issue went away.

it has just a clip either side of the unit so its a easy job to change

I will make this easy for you,assumming your
going to change them yourself

Bank 1 --is on the side of the engine that has cylinder #1
Bank 2-- is the opposite side
Sensor 1-- is the one closest to engine
Sensor 2 -at converter outlet,those don't fail as often

If you have a bad O2 Sensor, your going to change
both (2) Sensors FRONT 2 only
They are the 2 closest to the engine

O2 Sensors- failed or not, get changed,front 2 only
at 100,000 miles.

For 1997 Mercury Grand Marquis 4.6L SFI 8cyl the Oxygen Sensor is located: Under vehicle, passenger side, below seating area, mounted in exhaust pipe in rear of catalytic converter

Application: Number three


Hope helps (remember to rate this).

The Crankshaft Position Sensor is located: Under hood, driver side, front engine area, mounted rear of crankshaft pulley
The Knock Sensor is located: Under hood, center, front engine area, below intake manifold, mounted on block

Have you changed all the plugs to platinum and wires? My xterra was doing that and I changed all of them and now it runs great. Also, I changed the distribitor cap and rotor button.