a/f gauge install
 

Hey I'm trying to install an air fuel ratio gauge in my 3 and I'm wondering which wire I need to splice off of for the sender wire on my gauge. I looked tonight and the wires I saw were white with blue stripe, blue with red stripe, black with red stripe, and gray with blue stripe. Any help with this would be much appreciated. Thanks!

EDIT: For clarification I am talking about the wires between the ecu and the o2 sensor plug.