Considering the above mentioned image the choose off heading straight down on all 4 ITBs may be the outlet of your small gap just because of the throttleplate (on my ITBs there is no vacuum there - i.e. useless) Should really it sit on the throttle opener bolt at idle? https://jessei384cyu5.blognody.com/36791995/blacktop-4age-things-to-know-before-you-buy