ok, i have a b16a2 with drag turbo 370cc inj. 255 intank pump. vafc. ok when i go from a stop the car seems to to fine all the way through, but, when i go from any type of a roll when i hit 7000-7500 in 3rd &4th gear it starts to pop and lose power and blows a grey cloud of smoke out the exhaust. i have a couple theorys of what it is but i am not sure. any ideas will be helpful. thank you