The scanner does not know if you have a Fed or CA car. I know because I have one of each of the 99. Like I said before, I think it is possible your #1 O2 sensor (the one immediately behind the header) that is bad. Swapping the rear one is not going to help. One way to tell is to swap the sensors. I am not any expert but I had so much troubles with O2 sensors/CEL last couple of years and had learned a thing or two about these senors.