I have an 04 STi with up-pipe, turbo back exhaust(both catless) and an ecutek reflash. Recently I started to throw a cel code for runing to rich and fouling my first 02 sensor. I have thrown cel for the rear 02 sensor before and used a spark plug anti fouler with great success. My question is, can I do the same fix on the first 02 sensor?

Thanks in advance.