Ok, I messed with this all day. Changing the throttle setting alone doesn't do anything, as I suspected (why would it?). Changing the fuel settings to run richer does help minutely, but I suspect it is just because I am robbing power. There doesn't seem to be any reason the car SHOULD run richer NA. And even if I richen it up, it still does it, it is just maybe a little less pronounced. I've tried everything from -30 to -45 and it never really goes away. So does everyone with an afc have this issue?

 

well now that im boosting it doesnt do it, but it did before when i was n/a.

 

That makes me feel a little bit better. What is the minimum pressure your car usually hits when off-throttle? I'm wondering if it just doesn't go as low because of the FI and that stops the problem. Either way, you've given me some hope