I would be very appreciative if anyone can offer some help. I have a 2006 V6 4WD. I have been getting an annoying hesitation/surge feeling like if I was pushing/releasing the gas petal. No CEL and no error code reported. I am getting about 19-20 mpg on the highway. Bought obd sensor and was able to collect some data when car idles at about 700 RPM. Collected data for about 300 seconds idling at 700 rpm and everything looks very flat other than the downstream o2 sensors which they oscillate with the left side oscillation range being almost 2 times that of the right side. I have attached plots of actual data. Do you think the downstream o2 sensors are failing or is this normal for idle conditions. Car has about 180k, plugs were replaced about 30k ago. O2 sensors have never been replaced. Thanks in advance for your help.
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