There appears to be a vacuum port right under the MAP sensor on the throttle body. I don't know what that hooks up to and I checked my helms and that port doesn't exist on the USDM B18C1 throttlebody. The car runs fine with it being open and there appears to be very very slight vacuum on it by a finger test. I just have it capped off since nothing hooks up to it on the GSR. What is this port and do i just keep it capped off?