Air/fuel Gauge Question

[muzicmax]

I have a 2003 Gt. I want to install a A/F gauge. I went to the Glowshift site on how to install. It says:

Air / Fuel Ratio: Connect the green wire to the vehicle oxygen sensor signal, before the catalytic convertor. You may connect this
wire directly to the ECU harness or splice into the signal wire
leaving the sensor. This wire color can vary, be sure to consult your
vehicle’s owner’s manual. (0v ~ 1v Output - NARROW BAND
ONLY)

Am in the category NARROW BAND ?
I don't have a catalytic converter. I have a Catless 3 " downpipe.
I'll admit I'm not good with this kind of stuff....
I just want to hook up to the signal wire or the oxygen sensor wire i'm not going to attempt hooking it up ecu harness so that's out of the question
Is there something I can tap into on the fuse box inside the car or in the fuse box under the hood?
Any help would be appreciated!

[pdbrains]

You have a narrow band sensor. Unless you have a wide band sensor the gauge will not really be accurate for air/fuel ratio and will not serve any purpose except to tell you if you are really lean or rich. The narrow band sensors switch around an air fuel ratio of 14.7:1. Since you have a catless down pipe it should have a bung to add a wideband sensor. Do that, and at least you will have a gauge that you can tune with. Unless you are just looking for just a gauge with nice flashing lights. If you want that just splice the narrow band gauge into the O2 sensor wiring.