nothing at all
i got a wideband but yes you right, leaner is meaner but then to lean will cause detonation and break stuffThere is no perfect A/F ratio. Your engine might like 13:1 whereas mine likes 14:1. You can't know this unless you put it on a dyno with an A/F meter so they can see how different ratios affect your HP numbers. A good tuner will tune to highest HP and not to a specific A/F, IMO.[/b]