idle problem...please help!!!!

[MDM]

The o2 sensors are in your h-pipe, which also contains the cat(s). It attaches to your headers. When you raise your car, you will see 2 welded fittings in the h-pipe and the o2 sensors will be screwed into them. 3 wires will run to each sensor, as mustangs use the heated variety. Hope swapping them out fixes your problem. I usually replace o2 sensors in the neighborhood of every 50000 miles as preventative maintenance.