too lean bank 1 on a 2005 Nissan altima 3.5l v6

Question

I have a 2005 Nissan altima 3.5l v6 code showing too lean on bank 1 I need to know is that upstream or downstream

Answer 1

If there are no obvious vacuum leaks, the problem could be the Mass Air Flow Sensor (MAF) or clogged fuel injector. I rarely see at the shop a lean system code when the problem is the O2 senor. I recommend starting by adding a fuel additive and high octane gas for a couple of weeks.