Have no idea what this plug is for or what it does. Been searching around and ..nada. I thought at first it mighta been a o2 sensor plug but it is only a 3-wire. Please shed some light on a feeble mind. It is from an OBD2 B18C1 on the passenger shock tower harness. Have my GSR ECU coming in the mail so I can chuck my hacked P28 out the window. <_< Now I also am not positive of the year of my motor. Is there any stampings on the block or otherwheres that would say so?