Alright here it goes. I took my car for it's first road trip and noticed at around 80mph in 6th gear, if I let off the accelerator real fast she would start to sputter. It will do that in 4th gear as well going slower. Just want to see if anyone knows what this is. I look at my boost guage when this happens and it always around the 12 mark in the back vacuum ( i guess that's what it's call). Any input would be nice.

 

well im thinking becuase of the high speed its just the wind pressures acting upon your car. Do you have your plastic undertray removed? if you do that could be a source of the problem. Also the ECU on our evos delays RPM decrease when you lift of the throttle. I think what your experiencing is normal and dont need to worry about it, just log to make sure though, "lift off detonation"