Wierd Idle issue

[FeaR-GSX]

Ive had my GSX running for about 6 months now. it has a rebuilt stoc 7 bolt with a big 16g.

Ive researched and tried tuning but i cant seem to fix my idle.
1. when i did my boost leak test everything was fine except for my non-recirculated HKS BOV was letting all the air out instantly (is it supposed to do that?), so i blocked it off and everything else held pressure fine.
2. Ive adjusted the BISS screw and the screw that pushes on the throttle plate behind the Throttle body and still my car wont idle on a cold start. i have to give it gas until it warms up and even then when i press the clutch it will idle at 650, 900, 1100, or even 1500 rpms, and its different every time.
3. whenever my car is stopped and at idle my boost guage shows only 5-10 inches of vaccum instead of 17-18, but when im driving and let off the gas and press the clutch it stays at 17-18.
Its really wierd and this my first dsm so im not familiar with these issues
I DONT HAVE LINK
can help me diagnose this problem btw: it has a brand new IAC motor and it didnt fix it
Thank You

 

[OakStreetTuner]

That is some seriously low vacuum at idle. have you checked to see if there are any vacuum leaks after the throttle body? Perhaps your intake manifold gasket is not sealing. As for your bov, the fact that its not recirculated will most certainly cause issues, but it should hold pressure up to a certain point and than open. At what pressure were you performing you blt?

 

[FeaR-GSX]

i was pressurizing it up to 30 lbs but it would let air out as soon as i started pumping in air(i could hear it, not a hissing sound letting air out slowly but more like a swoosh letting it all out at one time. I didnt check after the TB but i guess ill do it saturday when i have time. i read that adjusting the BISS screw 2 full turns out from completely closed is a decent estimation for stock setting, is this true?

 

[bagii]

When you're car is idling, try spraying some starter fluid around the intake manifold and gaskets and if your car starts getting rev-happy, then you know you have a vacuum leak somewhere.

 

[FeaR-GSX]

So I just sprayed starting fluid around the throttle body and intake manifold gasket and it revved up on both gaskets so I guess I'll go get 2 new ones and put them on this weekend.

 

[FeaR-GSX]

I took the throttle body off and cleaned it, reset the SAS screw back to stock, cleaned and reset the BISS screw and put a new o-ring on it, Checked my FIAV which was good, and put two new throttle body gaskets on it. Then i started it up and it shot all the way up to 4000rpms and stayed there, so i shut the car off after 5-10 seconds. I readjusted the throttle cable to make sure it wasnt snagged on any vacuum lines and turned the BISS screw in a little bit. (The anxiousness was building, i knew this was going to fix it!) I restarted it and it went up to 1500rpms and stayed there, so after some BISS screw adjustments I have it down to a steady 775rpms, and it fixed my cold start issue. This morning it started first try without me having to hold the gas pedal and idled on its own!