Hyundai Repair: 2000 elantra, oxygen sensors, oxygen sensor

Question
I have a 2000 elantra. Sometimes the engine will miss when
idling or when the ac is on and accelerating.  I think I will
change the plugs and oxygen sensor.  Can you please tell me
exactly where the sensor is located?  thanks

Answer
Hi, Steve.  Your Elantra has two oxygen sensors.  The upstream sensor is in the driver's side of the exhaust manifold and the downstream comes out of the top of the front exhaust pipe just behind the flex-pipe area.  

I *do not* recommend replacing the oxygen sensors to address a misfire issue.  Your upstream oxygen sensor affects the fuel mixture in all your cylinders equally, so it cannot cause a power loss only on one cylinder.  Your downstream oxygen sensor is present to assess catalytic converter efficiency only, and doesn't affect fuel mixture at all.