Where do I plug in the front o2 sensor? There are three plugs I see that match up...

1. By the firewall with the emission stuff
2. Comes out of the harness with the coolant temp sensor and all those plugs on the passenger side of the motor (I think the CAS and stuff?)
3. Comes out of the harness with just the MAFS plug.

I doubt its #1...I tried #2 and #3 but I can't really tell the difference.

Any help would be appreciated...thanks!

 

Tough question guys, I know....

I'm pretty sure its the plug that comes out with the mafs now, for reference.

 

CAS harness

 

Well thats really weird. The car runs alot better with it on the other plug it seems like...

Thanks for the pic and sorry for the apparent mis-info..I need to find out what that other plug is for now, lol.

 

hmm, the fan maybe? i dunno....also, put a voltmeter on the o2 sensor pin on the ecu with it plugged in and then with it unplugged and see if you get any voltage. just stick the point of the multimeter in next to the wire.