Log MAF specified, MAF Actual, MAP specified, MAP actual, and throttle position. Then warm engine, 3rd gear, 100% throttle, 2000-5000 rpm, repeat 3 or 4 times.
I am guessing either boost system leak or screwy MAF. I have seen screwy MAF's that bounce all over causing boost to jump up and down. I also had a OMI break a bracket that gave me an intermittent leak and cause my boost to meander. The 100% throttle eliminates adaptation.
Wavetrac LSD, PP520's with RC4, VNT17/22, Flying Kasper FMIC 3" OMI, Whitbread 2.5" downpipe, PD lift pump, South Bend Stage 2 Endurance Clutch, steel skid plate, Wingnut inspired EGR mod, MyCruiseAgent no drill EGT, MoGolf skidplate mod