Smooth idle, but lower vaccum?

[Jon91TSi]

Hey all,

Recently I have noticed that my idle has dropped from the 20-21hg range to 17-19hg range. My karman readings on my logger and AFC have not changed still in the 33-35hz range. My idle quality is still the same.. what could be causing this? It still burns 0 oil and runs smooth as anything..

Any suggestions?

Thanks

 

[PaleDSM]

Is the idle speed still the same?

 

[Jon91TSi]

yes it is.. stays at 750rpm within a 15-30 rpm window..

 

[PaleDSM]

I'd say to start looking for intake leaks in the injector/intake manifold/tb to intake manifold area.

 

[Jon91TSi]

I already put new isolators and O-rings on awhile ago as well as replaced the intake and exhaust manifold gaskets and tb gaskets..

 

[PaleDSM]

Have you pressurized the intake tract since the installs? If not I'd do it to make sure nothing went wrong and you don't still have a leak. What can it hurt?

 

[Jon91TSi]

any other ideas?