if its a 01 you should be boosting 9 psi but the highest spike that i have seen on mine is 12 psi

 

@lm0812 the most ive seen was 10psi a month ago

 

I the same problem few years ago, check attached photo. If you haven't already changed your stock crankcase breather and L-shape hose(also read this was recalled), change them with new version (got from dealer few bucks) I had a small tear in them.

 

@silver rings- thanks for the pic i ran my fingers around all those lines and didnt feel anything but i'm going to take them out and fully check them.

 

Do a boost leak test.... you won't have to pull anything out then...

 

01 should is .8 bar stock or 11-12psi. Can be slightly lower in cold conditions.

5psi tends to be limp since the N75 opens up all the time to allow the pressure directly to the WG which has a 5psi spring.

Pressure test is the best way to find boost/vac leaks.

 

http://www.a4mods.com/index.php?page...boostleak.html

 

Can limp mode be confirmed with a scan or vagcom?

After installing a carbonio intake and 007 DV, I went from 15psi to 5psi. I did a boost leak test and only found one small leak by my intercooler.

Any ideas?

 

Fix the leak by the intercooler and then see where you are at.

 

I'll be sealing it soon. It wouldn't make sense that that would be the source of the 10psi drop though.

I was boosting 15psi before working on the car that time, installed the intake and DV and was only boosting 5psi immediately after. I'll have to scan it and see if theres any codes.