You need a Wide Band O2 sensor and related electronics to get an acurate A/F ratio reading. Any of the Wide Band units work well, DynoJet Wide Band Commander, LM-1, ect.
On the 104-pin connector, the left 02 sensor is pin 87 which is a red wire with a black stripe. For the right 02 sensor go to pin 60 which is a gray wire with a light blue stripe.