Yesterday morning on the way to work my emission warning light came on I have a 2004 TL Auto with approximiately 98,500 miles. I went to Auto Zone today and the code is P2251 i.e. O2 sensor. From earlier threads I saw from year's ago ironically enough the sensor seems to go out at 100K how coincidental.

My question is what will happen if I do not replace the O2 sensor, I live in SC and there are no emission inspections but the person at Auto Zone said I would notice worse gas mileage and the car may stall. I have to drive out of town this weekend and will have to worry about getting fixed next week since I don't have time to get fixed this week.

How difficult is it to replace the O2 sensor before the Catalytic converter and does anyone know of a place to buy that is less than the $129 Auto Zone quoted? Is the person correct at Auto Zone that I will notice much worse mileage and the car could start stalling? Thanks in advance for the advice.

 

i am in the same boat as u man...trying to figure out with one i need to replace! but yea low mpg and stuff is what would happen if you dont fix it..good luck!

 

My go to repair man said it would take awhile before I really notice bad gas mileage and it matters which O2 sensor is bad. I plan on getting the sensor replaced if I start noticing bad gas mileage and other issues. Just a matter of timing and how much the sensor costs.