so here i am pulling the intake off this rx and notice a second o2 sensor right below the turbo but not hooked up ....

umm wtf ??

anyone got a idea why this has 2 o2 sensors 1 before and 1 after the turbo

by the way its a 86

I am under the assumption o2 sensors are always after the turbo. Perhaps the downstream one (factory one) becamse disfunctional and they weren't able to get it out of the bung. So they drilled, and installed another one?

I have no clue why you have that. Every turbo I've seen has the o2 after the turbo.

Someone replaced the uppipe on it with one off an EA81. My EA81T had it on the up-pipe, and when it went south, I replaced it with an EA82 one, and the EA82 one had a plug in the port. This is what leads me to believe that they jes used the same crossover from 81 to 82. Either that or a previous owner had an A/F meter in there, and put in the second O2 for it.