4G63 idle surge bad, bad FIAV?

[modicaUSMC]

So I have about 8 miles and 2 hours of run time on my fresh rebuilt engine, the idle is surging bad from 1200-1700 RPMS. I've checked everything!! 172 psi across the board and good oil pressure, head was rebuilt and all gaskets are new and torqued to spec with no leaks. the only thing keeping me from driving her is the idle problem.
-ISC is good
- throttle body shaft seals just replaced
-TB has new gaskets on both sides
- on SD V3 lite with the base SD map
- no wide band, just need to weld on the bung
- no boost leaks at all! I checked up to 15psi until my tester shot off like a bullet
- FPR set at 42.5 psi with Evo 8 550cc
- BISS is grounded out and doesnt change anything
- TPS set at .63V
-All settings in link are cherry and i have tried adding dead time
- I even hooked back up my 2G MAF and adjusted the airflow sliders and its the SAME outcome as SD

On SD at idle revs are rising and dropping bad, regardless of this surging AIRflowper rev is between .24-.26 and Fuel trims are -3% to +4% during surgeing, if i start decreasing airflow numbers it runs lean and the O2 goes from 0.00-0.02 and doesnt cycle at all. I f i raise airflow fuel trims go to +17% and revs raise, O2 cycles good but the surgeing gets faster and worse and airflowperrev goes to .30-.38.

This throttle body is off my talon, I swapped them because it would never idle no matter what we did. The only thing i havent checked is the FIAV, does anyone have any experience with high idle surgeing while warm before closing the FIAV... Could this work? I'm F'in stumped and feel like burning it haha

 

[ColtiXim]

Base timing 5° set ?
Active Idle switch ?

 

[modicaUSMC]

Yes. Everything is set right. That's why I'm wondering if the FIAV is the culprit

 

[jim95redgsx]

Unfortunately, there is no easy way to test the FIAV. Do you have the coolant lines connected to the throttle body? The FIAV closes due to coolant temperature and will not operate correctly without those coolant lines.

Idle surge is caused by too much air entering the engine at idle. You say that you did a boost leak test, so that should eliminate any external leaks (vacuum lines, etc). There are only a few places for an internal leak that will not show up on a boost leak test: ISC, FIAV, misadjusted throttle stop (idle switch on a 1G TB) or a too tight throttle cable (must have some slack at idle).

One item, often overlooked, is the throttle body to intake manifold gasket. This gasket has a tab on it that will stick up beyond the metal castings. You can see this tab just by looking at the TB. It must be on the top of the TB towards the firewall. If the gasket is installed in any other position, it will expose the air passage that feeds the BISS screw to the throttle bore. This will make the BISS screw completely ineffective as any air that would be blocked by the Biss screw will go directly into the engine.

Jim

 

[modicaUSMC]

**RESOLVED**
So I closed the FIAV and BOOM! Perfect steady idle. Everything in link looks good still other than some slightly high airflowperrev
Numbers. But she drives beautifully. ISC position is at 30 and idle set at 850. Warm up is a couple seconds of light throttle but once warm idle is steady and only fluctuates around 20 rpms