Rick,
If it cleared itself then I would just let it be until it comes back. When it does just replace the Oxygen sensor that has the bad heater circuit in it. That is all I did. I only have 2 OS2 sensors, but I think your V8 will have 4, My book doesn't have a definition for PO161 since it is only for the inline 6, not the V8. Good luck!
Brian

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Brian W. Heitman

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