I have a Faze 30 inhg and 30 psi boost gauge, it read pretty acurate but the problem is that when it reach full boost it would bouce back and forth like crazy.
Let say im running 8 psi, it would bounce between 7-9 nonstop, is this a problem with the gauge or something is up with the vacuum source it seeing?

 

i would check the vacuum lines.

 

could b da gauge too.... spring or something mite b weak...

 

There shouldnt be any vaccum leak because i idle at 21 inhg

 

i say you should bounce the gauge of the floor a few times, it usually works

 

Are you using a boost controller? Is this a new problem? Can you check your map sensor to make sure the boost is flucuating? What type of manifold and wastegate are you using?

Need as much relevant info you can provide.....your just stating a problem.