fwiw my 99 has always read ~18" of vacuum at idle here at sea level. Before and after the turbo (as if that even matters) and its well within compression specs.

 

ok so my vacuum is showing 18-19 now so thats good however my idle is still all rough whenever i rev it. In neutral if i rev it till about 3k and then let go of the throttle...the rpm goes down to about 200 and then goes back to idle. what the hell could this be? Seems like my idle air control is working so im clueless

 

That is DEFFINATELY a vac leak imo.

Check your bov to make sure its not opening near idle,

I had my bov way to loose, and when i revved it up to about 2k it would drop to 200 up to 1100 down to 200 up to 1100 pretty much indefinably.

Gl.

 

According to this, would my boost reading also be off? My gauge is showing 5 psi, does this mean its not actually giving 5 psi? Hmmmmm.

Someone enlighten me, id love to turn up the boost

 

no. Boost is boost, it doesn't change no matter where you are, however it may make your turbo have to work a little harder in order to reach the same pressure.

 

Im @ ~22in HG Vac, used to be ~10 ;p

Was fixed when I realized my bov was a piece of crap and plugged the vac line going to it...woah, +12in hg of vac! awesome!

lol, plug the vacuum line going to the bov, if it doesnt help, you bov ain't leakin. Easy test