so i installed an air fuel ratio guage and tranny temp guage to the a pillar yesterday, my only problem is the air fuel guage. The AFR has 3 wires, one ground, one positive, the the purple one which is suppose to go to the o2 sensor, but i could not locate the wire for this? any help please
also they were freebies.....

Is this a AFR gauge that uses your cars O2 sensor? These are not very accurate because they use a narrow band sensor, and you need a wide band to get accurate readings. The wire your looking for would be at your O2 sensor on your rear exhaust manifold. I'm sure which wire you will need.

i read in an old post it was a purplish blue one? and isnt the sensor on the cat?

Not sure if your year has 2 O2s, the one you want is before the cat on the manifold or the down pipe. If you have a second one it'* after the cat and it'* used to monitor the cat.

ok thank you very much

most cars not have 4 wire 02'* most of the time they have 2 whites that are 12v in a black for ground and a black signal wire. old cars have 1 wire so its pretty easy to wire it in lol.

also like said above the A/F gauge is about efficient as a strobe light in your face all the time. a good wide band runs about $200+ those will tell you what you need to know about how the car is running more so than a ~$40 A/F "strobe light".

well like i said i got it for free and since the computer moniters it for me i dont have to spend 200 bucks at this time haha, anyways i spliced into the purple wire on the o2 sensor which was at the back of the rea manifold. when i did this everything was fine, then it started to idle funny. it would lower its rpms then raise then lower, any ideas? also when i unspliced it the car idles fine.

Most likely change the resistance. And that will give incorrect reading form the O2 sensor.

how would i go about doing that

i spliced into it in the engine bay, should i have done it more towards the pcm?