A/F (Air/Fuel) Ratio

[Kaotic Lazagna]

At idle and cruising/very light acceleration, my A/F ratio (according to my SG) stays around stochiometric (14.5), but when I floor it (only tried flooring it in 2nd gear starting from ~10mph and in 5th gear starting from ~32mph), it goes to 15-17. That means I'm running lean when I'm flooring it. It should be going <14, right? That means my engine isn't getting enough fuel when I'm flooring it (car doesn't bog or anything, and actually accelerates decently despite my wheel and tire combo being 41.3 lbs). Maybe it's because of where I am in the rpm band when I was flooring it? I was in city streets, so maybe that's why? I'll try flooring it on the freeway in 3rd gear the next time I'm on the freeway. There were a couple of times that it briefly went to 12.8.

I also noticed that if the loop remained closed, and when I was flooring it, that's when it went to 12.8. As soon as the loop went to open, the AF ratio went to 15-17.x.

Should I be concerned about this, or not because I'm basing it off the Scan Gauge, and I'm not too sure where it's getting its readings from.