02 sensor help

[raging panda]

ok, i bought the car in october, not the best time of the year to work on your car. It ran fine through the winter, and still does, but i finally got time to work on the car. i then found out that my o2 sensor hasnt been hooked up since i got the car, and here is where i need help

where does the o2 sensor come from out of the firewall so that i can hook it back up, because its nowhere to be found right now

also, why is it that my engine still runs fine?

just so that i dont have to make another post, here is one problem i have been having but not a big issue. when i put the clutch or just take it out of gear, the rpms drop to around 300-400 and stay there until i come to a complete stop, then it stablizes at 750ish like normal, what could be the problem here, because otherwise it runs fine.

thanks for the help, i have been a member here for a while and havent posted because i sold my first s13 and loved it so much that i had to get another one.

[raging panda]

can anyone trace the o2 sensor wire back to the firewall or wherever it comes out of?

[Irving18m]

I know on my 1990 240 my one 02 sensor is right next to the heat shield on the drivers side engine bay, almost directly under the AIV. Good luck!

[raging panda]

thank you, i know where the o2 sensor is, i need to know where the wire is that plugs into the ecu.