Question…

I only have 2 Oxygen Sensors in this vehicle. One Upstream and one Downstream.

If I were to change the Upstream should I change the Downstream as well??

Why I’m changing my upstream you ask??

I am seeing noticeable affects off the vehicle running rich. Too much gas consumption than normal

  • RickMN@alien.topBEnglish
    1·
    10 months ago

    Doubltful that it’s caused by the oxygen sensor. Most common cause of reduced MPG is worn spark plugs. And to answer your question, no, you don’t need to replace the downstream because it has nothing to do with calculating air/fuel mixtures. Its only job is to monitor the cat performance.