u/Overall-Drag1484

So I have a 24 zx6r,recently bout 6-8 months ago,has full m4 exhaust,lifter sprockets ,air box mod,velocity stacks,and has ecu flash from Moore mafia,when I’m in 4th at 4k rpm as nd go wide open throttle it’s falls on its face,has the ecu replace still same thing,if I gradually get on it ,it does ok .Does great in rest of the gears ,just in 4 th no hesitation or anything just simply slow taking off at 4k,any ideas ?