I know there has been several discussion about this, but I haven't seen much about what this is exactly. Keep in mind, I know next to nothing about the setup of a 3800 engine. Here is what has transpired:
My check engine light came on in my 1996 SLE Bonnie and I went to have the code read at Autozone. it was P0135 x2, now I dont know if this is because of both upper and lower O2 sensors failing or an old code and the current code. I did notice my gas mileage went from almost 30 to 15mpg... since I commute 35 miles a day one way, I'd really like to get this fixed fast :
It is under the used car dealer'* warranty, so he will replace it, but I just want to make sure that things are getting done right.