I have similar problem. I have R33 gtst auto with electronic boost control, 11 psi, std turbo. Sometimes boost spikes ( for whatever reason) past 16 psi and wham! power cut, then ok again. Could be cold air, i have voltage bender to lower afm voltage so it does not max out. Still happens, i reckon voltage bender needs gentle signal increase. If its a sudden spike from say 0.5v to 5.5, its too fast for processor. This is all i can think of coz it's pissing me off to tell the truth.