im having this stupid problem with my boost guage. ever since i wired the light in the gauge wont show the correct vac. right now it shows 10 mmHg but before i took it off to wire the light it was at 25 mmHg. ive tried everything to fix it but nothing is working. im starting to think its the vac line i used to hook up the gauge. i used regular black vac hose and ran the line down the a-pillar and into the wheel well and i think i might be getting pinched somewhere. i had this same problem on my other tsi. what kind of line do you use on the gauge? i saw some white plastic lines that look a lot stronger and probably wont get pinched as easily.

That stronger white wire will not work unless the back of your boost gauge is a threaded fitting. That stuff is hard to find because it is usually 1/8 inch. Wire the line through the steering column boot. Just take a screwdriver and punch a hole through it. As long as you dont run it near anything hot, there is no way it would get messed up. Nowhere to pinch.