I am hoping he means what's the value of reading the A/F gauge when it really is not 100% accurate. At least I hope that is what he meant
What I mean is that
Why would the AF be wrong in the first place. What would I have to do to my car Mod wise to Require one of these. What add ons would affect the AF. I figure Cam Injectors things like that. I know that you do not want it to be to rich or too lean.