Maybe it may be part of a specific MFR's OBD data, but I don't think A/F ratio is part of the standard OBDII data that can be read from the port. By looking at the O2 sensor readings, and getting a feel for the regular range of values you get on your vehicle you can tell if you are lean or rich.
So far, all I've come up with is one for GM (which should interest Jay). In fact, it was right in the XGauge PDF on the ScanGauge website, along with transmission fluid temp and some other useful GM XGauges. I used it and found that mine stays steady unless I run WOT for more than a few seconds; then it can get as rich as 12:1.
I was going to add that I did it on my cav but it isn't a ford. mine runs 14.7 until I really get into it at which time it hits 12.6.
I wonder if you can compare other codes that are ford and chevy codes to see the difference and maybe apply those differences to the a/f ratio code. maybe it is just a few digits difference. the worst it could do is give you a bogus reading if you don't get it right. it won't screw anything up as it only reads the codes, it doesn't modify them.
I would look at it myself but I have found myself busier than usual here lately.
just an idea
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I'll have to look that up, but I was right, its not standard OBDII data, its mfr specific. I do have a gauge setup for tranny temp. I was watching that closely when I was suspecting transmission failure a while back.