Aww mine doesn't do that anymore, it was a very rich tune with retarded timing.. and I think a lot of exhaust/fuel vapours were collecting in the high flow cat.. and at the top of a gear change (6.5k in 3rd was good) it ignited a flame coming up to my back spoiler/window. I could see it in my rear view mirror!
Diff tune now and 3" de-cat
But the SAFC intercepts the signals going to the ECU from the AFM, and changes them.. so it lies to the ECU