Twin turbo AFR question. Lean spots.

Nixlimited

I think it's normal to go full lean on decel (with no pedal input) as well as after a rev when the car is not moving for the same reason: the engine is coming down in speed and there is no load so fueling is minimal while the vacuum is still pulling in more air than necessary. Not sure how long your AFRs are staying lean after a blip, but I wouldn't be too worried. I would only really worry about lean conditions under load.

With regard to your cruising AFRs bouncing all over, the car should be in closed loop fueling so could that indicate some issue with the OEM O2 sensors? Or maybe the larger injectors are not spraying consistently at such a low IDC.

__________________
Car Sold! Pleasure being a part of the Z community.
New ride: 2015 GT-R - 647 WHP / 641 WTQ (e85) & 543 WHP / 519 WTQ (91)