Right this is really confusing me. Ive just fitted a new boost gauge, it comes with its own pressure sensor which i fitted in the plenium, for some reason im not getting a negative boost reading. First thing i thought was the sensor didnt work properly so first thing i did was take off the intercooler pipe leading to the plenium and slowly moved my hand over the hole, and sure enough i got a negative reading. So now im really confused ive been told it is down to where i mounted it but surely the whole of the plenium would show a negative reading?????/