This was plugged in at O2 sensor, it has failed. Do I need it? Not a stock part, and can't find it anywhere. It looks like it has a resistor...or something in-line. I have plugged in O2 without it, and am no longer throwing a code.

 

This is what it looks like without heat shrink

 

Might be a short extension? Were they original O2's?

 

They are MIL eliminators. They give a reading to the computer, that bypass the O2 sensors.

 

Ak, where do I get them? Just in case?

 

They were "stock o2's, just had them in line with o2.

 

That is right. They plug in to the system to give a faulty reading to computer so you can run a rich/lean mixture. They run about 70 a pair but you can make your own. I saw a write up on it before.

If you want to read how they work. Check this out.

http://members.tccoa.com/tinman/MIL/

 

Thanks! I figured they would be pretty easy to make, and way cheaper too!