ok i have an air/fuel gauge right so i follow the directions and put it in and tap to the wire on the o2 sensor and it works and gives a reading, but some of my other friends had theirs done at performance shops. anyway my gauge just kinda sits at one point then as you rev it or drive it will move and then return to that point. Other peoples gauges when your car is idle the gauge reading will bounce back and fourth from lean to rich and then as you rev it or drive it moves either lean or rich. i heard there is a seperate sensor that you could buy that goes in the exhaust and u attatch your gauge to that. so what is wrong with my gauge?? and what is that sensor called?? and where might i get one??