O2 Sensor Breakout (Page 1/1) Stricken SEP 10, 12:38 PM I have discovered that the O2 sensor on my 88 Formula is flapping in the wind. I have looked all around including crawling under the car, but I can't find its mate. I think the wire is purple, but I'm not finding it anywhere. Does anyone know where it breaks out of the main loom and routes over to the sensor? The previous owner had a mystery green wire routed straight from the ECM through the firewall and tied in the general area of the O2 sensor, but the end was just hanging loose. Maybe they had it hotwired somehow? Stricken SEP 10, 12:47 PM Mystery green wire is actually spliced to a purple wire. Does anyone know if this is the O2 sensor wire? Some interesting electrical work going on here... Gall757 SEP 10, 03:34 PM purple wire....in lower right corner of this diagram. Stricken SEP 10, 10:39 PM quote Originally posted by Gall757: purple wire....in lower right corner of this diagram. Thank you. I ran the wire direct to the O2 sensor, and it appears to be getting the signal now. I will use this band aid until I do my 3800 swap.