TRC off... maybe u pressed a button or something something that switched your traction control off. If so, just press it again when ur done drifting like one guy said...
If VSC always on... dunno, maybe u screwed the Vehicle Stability Control and it needs checking...
dont know whats up with my setup, but lately (this month) i've had a few intermittent jerks when going WOT. first one was a few weeks back, after the toll, 2nd gear, 4k rpm, can't remember the boost. then...