Well I finally got around to putting in a boost gauge again because my other one got stolen, anyway since then I had the back half of my exhaust replaced.



My current setup is a gutted pre cat too 3" pipe all the way back (single pipe) with a resonator, it had a stock catback before. Now my boost gauge is telling me im onyl hitting 6 psi at the most. Ive looked over everything for vacuum leaks so I dont thing there is any.



I cant figure out why its gone down, I used to get nearly 10 psi now like I said its usually between 5-7psi.

Im open to suggestions thanks.

sorry its a s4.

Chances are you have boost leaks, I would bet the O-rings beneath the injectors, tb elbow, tb, tb to plenum spacer, ait sensor, etc are leaking.

Turbo could be on its last leg also. Hard to say when you can't see it in person...

im going to check it over again.... what exactly is an ait sensor?



If I cant figure it out im going to pull the turbo and check its condition.

I dont know where the AIT is on our cars, but I can tell you what it is. It's an air intake temperature sensor. Tells the computer the temp of the incoming air.

its on the throttle body elbow

Unless you can pressurize the intake charge, you're not going to see those leaking under boost. They may be fine at idle under vacuum...