I just baught an 88 dakota with a 3.9 that has the o2 rich code. As it is right now it has a 4 wire o2 sensor on the y pipe that is hooked up. Also on the drivers side manifold there is what apears to be a one wire manifold that is not hooked up. Is this supose to be hooked up? and if so how many wire is it supose to be? Napa only showed one and doesn't list a location so any help would be apreaciated. Thans