Ok currently I have a Y4 throttle body on my Y8 turbo charged engine. atm it is still untuned and its idling up and down (i think its cuase its still untuned?) however someone said it might be due to the throttle body im using. I just want to know if there is acturlly a difference between the Y4 and the Y8 throttle body and what is it? could this be cuasing my idling problem?