JDM PW0 wows.

[EFSiR]

This is a B16 NA, running on Non chipped PW0. For some reason, the ECU throws code 2 which is #2 Oxygen sensor fault.

This only happens when I'm decellerating in gear with closed throttle body from say 5K RPM to 2K RPM.

Any ideas why?
TIA
Charlie

[Javier]

Most likely it needs both o2 sensors.

[EFSiR]

Both o2 sensors are new. I've adjusted the TPS sensor to be dead on at 0.5V. The original JDM one was close to 0.6V. Would changing it back to 0.6V at closed position help?
TIA
Charlie