My check engine light is on and the code indicates lean condition on the right and left heated oxygen sensors. The manual shows 4. Are they all the same or are they location specific? Rich W

 

I wouldn't go out and buy new o2 sensors without troubleshooting the situation. Most of the time those codes with the o2 sensors is a symptom of another problem elsewhere.You could have just a simple vacuum leak or fuel delivery issue.

 

Please include your Year and Model --
Your Oxygen sensors are installed in the exhaust head-pipes, 2 sensors on each bank -- each bank has 1 sensor ahead of the catalytic converter, and 1 sensor behind the cat.
On the 95 MERC, the sensors AHEAD of the cats have a different part number than the sensors BEHIND the cats..
Front sensor - NTK part # F4ZF-9F472-BB Green Jacket -- 16.5 inches long.
Rear sensor -- NTK part # F5AF-9G444-BB Blue Jacket -- 16.5 inches long.
I replaced all 4 sensors with the same part # ---- BOSCH #15717 (Made in USA) -- Blue Jacket -- 16.5 inches long.

 

Thanks 95 MERC. My car is a 96 Grand Marquis. I thought that was already listed. Rich W