i have an a4 1.8t and just recently started running 5psi. I immediately checked the vacuum line from my boost gauge and found no leaks any suggestions?

 

Do a boost leak test... probably popped a line or check valve.

If you don't know how to do a boost leak test go to the diy here at AF and look at the one I made for it...

 

okay thanks I will be sure to check it out.

 

Did you do any modifications to the car prior to the boost decrease?

What chip were you running?

 

No chip. All stock besides a cone air filter. Well i had the check engine light on because of a bad mass air flow sensor which caused my boost to decrease to 5psi. After I put a new one in, I plugged my friends computer into the dash and no codes came up so the check engine light is gone but it's still running 5psi.

 

What psi were you seeing before? 5-7psi is normal for a stock ECU.

 

So 5-7psi is normal for a stock turbo? Someone told me its suppose to be 10psi.......

 

what year?

 

2001........

 

Searching for a4 1.8t stock boost led me to this thread: https://www.audiforums.com/forum/nitrous-super-chargers-turbos-26/02-a4-1-8t-how-much-boost-54558/.

You still haven't answered how much boost you were seeing before.