After searching, i've tried all recommended tips and went through the manuals, but still idle is 2k at startup and lowers to 1500 when warm and won't go any lower. It's a 95 gsr with skunk2 IM and stock TB.

- I cleaned fitv and screwed white piece all the way in, and cleaned iacv
- no vacuum leaks. engine shuts off when I cover TB
- even when warm, the lower hole in the TB sucks like crazy. when i cover it the idle drops to almost normal
- when i pull the iacv plug off, the idle goes UP like 200 rpms

when it's still sucking from the lower hole does that indicate a problem with the fitv or TB? everything was working fine with idle ~500 before i switched IMs. any suggestions would be awesome as this is getting f-ing frustrating.

 

try messin with the idle screw on the TB its a flathead screw.
you said that when you cover the lower hole on the TB the idle drops to almost normal, well your car should bog and eventually when u do that !!!!!

 

Sounds like you missed a vacume hose somewhere.

 

deff sounds like a vacuum leak SOMEWHERE.

 

Did you bleed the cooling system after you installed the new IM? air in the cooling system will cause a high and sometimes fluctuating idle.

 

I bled coolant and had no effect.

i thought once the engine is warm it's not supposed to have any suction from the bottom hole on the TB since it should be sucking through the top to the iacv?

i'm going to put on the ITR throttle cable and bracket and see if it changes anything...i didn't think it needed it cuz there was still a little slack in the cable after install.

 

when the TB is sucking from the bottom hole when warm, does that mean there's a problem with the FITV or does it mean the TB is bringing in air from somewhere else?

 

sounds like you may have left some old gasket on the head. A guy brought his LS to my shop because he couldnt fix his high idle. he had missed a bunch of old gasket and it was sucking between the manifold and the head. try spraying some carb cleaner around where your IM meets the head.

How high is your ilde btw?

 

My friend had high idle because his throttle body would stick open some and we could push it closed where the cable attaches to the throttle body and it would go back to normal. Also before that he had the wrong throttle cable and bracket and it was adjusted to tight so it stayed open to 2000 rpm, but when we loosened it up so it would close perfect it would only open like 75% at full throttle. Then the ITR throttle cable and bracket fixed that