My F150 check engine soon light came on, so had it "plugged into", and they said I needed a new sensor. This was about a month after I put new plugs in it. Then I had em reset it for me after replacing the sensor they said was needed. Week later, light comes back on, and they say I need a new sensor on the other bank.....is this common for em to wear out that close together? I'm wondering if there was some confusion as to which bank sensor was bad. Darn things are $50 apiece....Ouh! This was an auto parts place, not a garage, and I just put the new one in they told me. It's not a hard job, but costly, and just wondered how common this is. Thanks for any info.