I'd bet your 2nd post has to do with this. If there are different parts for different years then there's a reason for it. AFAIK, o2's don't change from rich to lean at idle, that's why when you do the heated o2 sensor test you're instructed to hold steady at 2k RPM's. Also, when using datascan and the o2 drops to 0, does your car feel like it's misfiring, or does the "performance feel" not change despite weird readings from datascan?
