P0031 after resetting PCM :-(
 

I had a CEL p0037 since i gutted my cat and added a wideband.

But just yesterday i took off my pulley kit and installed my Injen intake and put OEM pulleys back on. I got in my car turned ignition on (not starting car) and press brake 20times rapidly oil pressure sweeped half way.

Well after i did that i noticed my AFR changed to being really rich. before i installed and cleared the PCM my aft wher just right around 15.0 crusiing now there in the 11 and 12's.

why would it do it right after i resetted my PCM.????

can anyone help?

I don't know why it would do it, but it means your front O2 sensor is bad

Resetting the PCM (brake pedal) resets the fuel trim.
Give it a few drive cycles and see if it goes back to what it was.