Yes, no matter how far I change the fuel up or down at idle, the o2 always cycles between .2 and .8. AFTER the ECU adjusts for a few seconds. Last night, I re-checked everything, then re-installed the AFC, reset the ECU, initalized then reset the AFC settings, and then cranked it up. As it was warming up, if I leaned out the fuel at 1k rpm, the car would start to stutter and pop (what I expected), then if I went rich, it would smooth out and raise the RPM.
Ok, so this told me that the S-AFC was DEFINITELY working at first, but then once the car got fully warmed up, I found that I could go all the way to -50 without the car idle stuttering or popping, so I got really confused. That's when I tried going from one extreme to the other quickly. Well, when I went from -50 all the way up to +20, the idle change noticeably and the O2s were spiked. I then did the opposite thing...I went from +20 all the way back down to -50, and the o2s bottomed out while the car nearly stalled. What happened each time, though, is that the ECU corrected itself and brought the idle back to normal each time as well as the o2s. Now, how is this possible? The tuning guides I've read have said that you should go lean until the exhaust starts to pop and start tuning from there, but my car keeps correcting itself on the fly. It takes a few seconds, but the idle always goes back to normal, and the o2s always return to the normal cycle.
I then did a 2nd gear pull (simply can't afford to do a 3rd gear pull anywhere late at night) with the S-AFC set to 0% across the board, and I finally saw what I expected: .95-.98 from around 4500-7500rpm. I then leaned out the settings from 5-7k and ran again...this time everything was .91-.93 in succession except for one dip from .93 to .91 then back to .93. I decided to richen slightly at this rpm (~6200) to compensate. Timing also rose gradually into the high teens until it maxed at 20 at 7200rpm (sounds good). It was midnight, and I was happy to at least see the S-AFC doing something, so I called it a night. The readings could be very different on a 3rd gear pull, but I just couldn't do it yet.
Strangely, my Karman peaked at 1589 during both runs, so I don't know if I'm getting any benefit or not. When I first put on the S-AFC and gave it similar settings, I was hitting 1612 (7400rpm) in 2nd, 1632 in 3rd (7400rpm), and 1659 in 4th (6900rpm). Last night was considerably warmer than when I got those initial readings, but the main issue is that the peak air flow didn't change despite the better o2 readings with leaner settings. Oh well, I guess I will only know on a dyno...