00' Explorer O2 sensor which ones?
My check engine light has been on for awhile and I just got around to taking to Advance Auto and they checked the codes. Popped P0171 and P0174, says Bank 1 and 2 running lean. Question is, which ones are they, the ones upstream or downstream. Seeing as they are running about $60.00 each and there are 4, I'd kinda like to know which ones are the culprits. Any help would be appreciated.