I was helping a buddy out with an off road Xpipe but his car is still throwing codes.
04 GT
I got the MIL's installed but there is another plug on the other end. am I supposed to plug the 02 into that end also??

on my GM I just plugged in and forget about it but it's diff on this mustang.

I Am so confused...friggin mustangs suck...hehe j/k help me please...