Not the Mike, but a Mike never the less.
I had a AF meter in my truck at one time. Thought it was something I couldn't live without. The Autometer one no doubt. Trouble is, I still have my EGR and all emissions stuff hooked up and working. The EGR and AIR pump play havoc with the AF meter, deluting the exhaust mixture so my gauge bounced around something terrible. So I pulled it out and sold it to someone who doesn't have emissions crap on their truck, and could actually get some use out of it.
But, to get to the point. The AF ratio meter uses a O2 sensor in the exhaust , just like it would for a computer controlled vehicle, except all it's doing is sending signals back to the meter as to what it is seeing, rich or lean, or the best stowick (sp?) This is right in the middle where it should run at normal cruising.
I bought a kit from Autometer for this, which is the wiring harness and O2 sensor. Not cheap for sure. Costs way more than the gauge. I guess the reason is because it's a heated type or something like that.