Rich,
As you have probably read in the other thread, even a new MAF has not solved the hesitation for me.
I just don't know what to try next.
Thinking out loud...its as if the DV is sticking open...but that can't be because its a Forge 007P (they don't stick do they?)....what controls the DV....on my car the N249. If the DV was to be stuck open....then you could press the accelerator all you want...boost would be created, but it would be immediately recirculated. But surely I'd hear that? So in this scenario it could be either the DV or the N249.
Likewise...the N75 controls the vacuum which operates the wastegate. My N75 is new, but perhaps the wastegate is sticking?
It could be the throttle position sensor or throttle body. One or the other could be sticking, or producing a strange value, causing the ECU to get confused.
Finally, it could be a vaccum or boost leak somewhere. Perhaps as the engine gets put under load, the engine will move, flexing/moving the pipes (we've all seen it on the dyno how much the engine moves)...so perhaps when the engine moves, its opening up the leaking pipe somewhere?
End of my ramblings. I'm sure there's other things it could be too. What a nightmare.
AL