I just installed an autometer boost gauge on the ol STI and above 15 vacuum and into boost it makes a type of air noise. Not like a leak because it is reading accurately and I did the old soap and bubble test and got none but it seems to be an air noise that pulses with the engine. I have had multiple turbo cars before and a few autometer guages in them and I don't ever remember them making noise. Might it be defective or could the gauge it's self inside of it be leaking. Again it reads accurately so I don't believe it's leaking. Any help would be appreciated.

 

where did you tap into the vac line??

The guages make a little noise when the needle moves but it may have a leak inside.