I have a universal fuel reg with gauge with in and out and then the small vacuum pipe. All is connected except for the vacuum pipe.NOW can this cause probs or do i have to drill and fit pipe to manifold.does it cause a jerk when you put foot etc,etc. google shows a bit but there are also others that show you can leave it open. I already have a prob with petrol flowing out vac pipe so i suspect pressure was to high and i damaged the diaphragm. I also read pressure should be 40--43psi.Can anybody with know how give a bit of info. thanks