Rb20 High Idle! I've Checked Most Sensors! Help !

[cabramatta]

Hey guys, I've been having this issue with my car for a while now.

I've changed:

TPS

AAC Valve

Air Regulator (IACV as some call it)

Spark plugs

Cleaned grounds

Sealed up coilpacks and they are all getting voltage

Tightened all cooler clamps

Made sure there are no vac leaks

At idle, I'm getting -12 psi vacuum, I've read that normal vac for a silvertop RB20DET is -17~

Before anything, I would like to state that there is a hissing sound coming from right behind the throttle body (on the plenum). It sounds like the throttle plate isn't completely closed.

I've adjusted the TPS as per factory specs with an increase of 0.01V.

Apart from the car idling at around 1.2 - 1.5k, it drives perfectly fine. Sometimes however when it warms up, it will idle very low and completely die out if I don't keep tapping the throttle.

I've removed the CAS and spun it and I can hear the clicking sound from the injectors, but it seems like the click only comes from one of them right near the throttle body, I can't FEEL the click even when I placed my hands on all the injectors, but I can certainly hear it. Is this normal or should all of them be clicking one at a time each time I spin the CAS ?

I've screwed the idle screw all the way in which made no difference, only when I screw it counter clockwise about 3-4 times it starts idling higher than it already is.

The car starts fine, doesn't struggle, I don't even need to tap the gas to start it when its cold. It just seems like it's always stuck in coldstart.

I tried blocking off the air regulator aswell which made no difference so I put it back in.

I've tested the Air regulator and its shutting close when warmed up so that states that its not leaking from there.

The thing is, I can't check timing on it since its idling over 650RPM. I've read that car must be idling at 650RPM and to make sure its 15DEGREES as long as timing is all correct at TDC with lines intact.

The half moon key inside the CAS is also fine, not broken.

Any ideas ?!

[Moodles2]

If it's stuck in coldstart as you say, then the coolant temp sensor that runs to the ECU might not be functioning