Did you replace the bad sensor with the Nissan OEM one or an aftermarket? There have been reports of continued codes if the sensors are not identical units.
The HFC wouldn't have any effect on the sensor 1 codes as upstream O2's are located in the header collector
__________________
AAM | Dynosty | Ecutek | Eibach | Hawk | H&R | Nismo | Stillen | Stoptech | Z1
|