P0131 only under certain conditions

[stevedenali]

Hi, I have a 2005 Sierra Denali. I keep getting a P0131(O2 sensor circuit low bank 1 sensor1) so that’s driver side before the converter. It only comes on after I floor it to get on the highway or am towing and have to floor it. The truck never runs rough or any different it seems with the check engine light on. I just wanted to see if any of you guys have had this happen to you before and If you think it’s a sensor or wiring, or something else....thanks!!

[JJJimmy]

I'm having the same issue I think. 97 Savanna 3500 drives fine in town, but as soon as I try to drive on the highway it looses ALMOST all of the power, I can drive on flat road at 70mph but no hills. If I have to start from a full stop it takes like a full minute to get up to 40mph. Only the very first part of the gas pedal range is useful, more than an inch into the gas and I can feel it bogging down.