Got my S4 about 2 weeks ago, it's been running great. Put in a Blitz DTT turbo timer/boost gauge about a week ago. Turbo peaks at .7 bar and level off to around .6 bar. Good stock boost level. Since yesterday, the car will run to boost at the beginning and after driving awhile, it will only go up to around .4 bar at the max. It runs like a dog!!
I don't hear any sound that sounds like air leaking, if it was leaking, then it should be at low boost at all times. So what's wrong with the car? Humid air? Please help. And the car is a 2001 with 10k miles 6-speed.
Thanks!!

 

What PSI is it peaking at ?

 

it usually peaks at 10 psi, but sometimes as i stated before it only goes to about 5 psi.

 

Hmmm
thats not right , maybe a leak .

 

i know it's not right. But the problem is that sometime boost will be full and sometime it will be half!! It's driving me nutz. If there was a leak, wouldn't it be half or low boost at all times? And no check engine light either.[:@]

 

check your throttle body boot because the same exact thing happened to my s4