oxygen sensor

Hi, I'm new here although I have known of this site for years. I am a G20 owner from way back - I have owned one continuously since 1992 (I have owned 3 in that time). I currently have a 2001 G20 with 86,000 miles on it and just the other day the "service engine soon" light came on so I took...

I have read so many conflicting statements about how many, where, etc. regarding the O2 sensors in my car. Can anyone please help and be as specific as possible. I have a 2002 G20. It threw a P0138 code last week. We reset it and it threw it again a few days later. I have roughly 115K on my...