I just installed my Cobalt A/F gauge. For anyone doing this on a 07 V6 you will need to splice into the grey wire with a Lt. blue stripe off the PCM. It is located on the bottom connector off the PCM, pin #28. This bottom connector is the one that has the matching wire/ pin combo. The first one doesn't have pin#28 and the second one has a white wire w/red stripe.

After it is all connected and running it sweeps from red- lean to Green- Rich. Looks cool. Too bad it isn't backlit like all my other Cobalt gauges.

 

I have the Nexus A/F gauge, a little easier to hook up, since the nexus has the sensor remote module. Still the Cobalt gauges are nice. I had the cobalt series when I was first sponsored by Auto Meter, But last year they up- graded my sponsorship to the Nexus. But trust me there's nothing wrong with the cobalt series! Very good gauges...