Thread: P0140 code help

So after further research and learning the differences in how manufactures monitor cat efficiency the electrical circuit i made will not work for 2000 GM vehicles.
The computer is looking for a fluctuating passing examples 4.5 to -4.5 volts passing zero. The circuit i made dropped the voltage but did not allow it to pass zero. This worked on my Contour SVT because it only looks for a voltage delta front to back.

I was able to get the code to stay off by removing the circuit and installing 2 spark plug non foulers moving the sensor out of the main exhaust stream.