Depends on year to 93 there are 2. 94 and later there are 3 (one post cat)
in the car
It is caused by Bank 2 Sensor 2 oxygen sensor failing.
inside the exhaust and by dissasembling and swapping it out
18 Millimeter, 1.5 Pitch
Let me know if you find out. i am having trouble locting which one is 1 and which is 2... I was told i needed to replace the #1 oxygen sensor
The sensor runs under the seat and out to the exhaust pipe under the back of the car. You will have to remove the two bolts holding the seat to replace it.
Cylinders 1,3, and 5, the sensor after the catalytic converter. Find the exhaust pipe coming from the front of the vehicle and follow it until you see the O2 sensor after the catalytic converter.
It is under the intake manifold
The 2001 Lexus coolant temperature sensor can be found on the front of the engine. The coolant temperature sensor will be in the vicinity of the thermostat housing.
The IAT sensor is mounted on the mass air flow meter.
There are 3 Oxygen sensors on Lexus RX300. I have replaced the 2 forwards ones so far. The third one is Post- Catalytic converter and requires drivers seat removal to get at the electrical connector. It is also difficult to remove the O 2 sensor from the exhaust system because it is mounted into an exhaust hanger.
under the intake manifold