Great, thanks. I looked at those time stamps. I have never seen a WB react that fast! It looks like you are running about +7psi boost when it goes super lean. I did a little research and found some information that says fuel cut on a 7MGTE comes in at around 1400-1500Hz. You are hitting 1347Hz peak (fuel box) which means you might be hitting the OEM ECU fuel cut. Previously I thought your output was down around 400Hz. Set the VKF Clamp to 1300-1400 and see what happens. Remember you need more injector and/or more fuel pressure to give you the head room to avoid fuel cut. These 7MGTE's don't have a MAP sensor fuel cut like the 2JZGTE, they use the air flow meter signal. I am a little surprised you are hitting fuel cut at only 7psi. Mind you, you are super rich before you hit 1347Hz so I think you need to pull the whole fuel table down to compensate for the additional fuel you have, especially under boost. It jumps up when you hit 4psi.

BTW, super rich is a good problem! It means you have lots of tuning room to achieve your target boost levels. Not sure if 550cc injectors are enough for 20psi though, but lets see when you get this fuel cut under control.