Wanted to run this by you guys and see what you thought.. I've got a loud whistling under the hood of my car.. gets louder with RPM. Also, sometimes after I decel and am sitting at a light, it idle's really high (around 2k) for a minute before settling back down.

Vacuum leak?

 

PCV system most likely

Inspect for rot

 

definately sounds like a vacuum leak, take a can of brake parts cleaner (de-natured alcohol) while it is idling high, sparay it all around the intake and vacuum hoses, you will know when the engine sucks it in, easy way to find the leak.

 

Car has a brand new LS6 PCV conversion.. so I can see the tube and it's not that. I'm pretty sure it's leaking around my FAST intake somewhere.

 

My car did the same thing it made a loud wistling noise and the idle would hang and it got worse until I bought new gaskets for my intake and fixed it you have a vacume leak I would do what Rocky70304 said to find it.

 

Are you still using the EGR?

 

No emissions. I used new FAST gaskets when I installed it.. I have a feeling it's where the upper half meets the lower.

 

Did you use the valley cover bolts that came with the FAST intake?

 

My car also has a loud whistling noise, but it seems that it is coming through my factor speakers. I am not sure if the alternator is causing rf interferenece or what is actually going on, but its very annoying. Have any of you guys had RF interference using msd wires?

 

never had any rf with msd wires, you might look and make sure you don't have part of the covering burnt off of one by the headers. You also may try running a good ground to the engine and to the body to see if that eliminates any of it

 

After i installed my ls6 pcv my car idles high also and it whilstles somtimes while accelerating. It usually idles around 850 rpm and when im rolling and put the clutch in it likes to sit around 1000-1100rpm untill i come to a stop then it settles back to 850 or so. I tried the brake cleaner thing but had no luck. Damn car has had idle issues ever since my o2 extension got torn up and caused a fuse to blow. After i replaced the fuse, o2 extension, and fixed all known vaccum leaks it still idles a little high. I think i have a small leak around the small vaccum line on the back of the intake b/c it sounds like the whistle is coming from the back of the motor. Id pull the intake off and inspect the gaskets and the small vaccum line. Ive heard that vaccum line is easily damaged and some people claim that you arent suppose to re use the intake gaskets.

 

Anything above 2 mph the throttle crack is enabled and it is disabled below 1 mph. That is just part of the tuning, but it can be tuned out with hptuners or efi live. Your car only goes into idle state basically when it is not moving, basically the IAC motor opens up, but you can control the amount it opens, hence "throttle cracker". So if you push in the clutch while you are above 2mph your car will never go into an idle state until you stop. Nothing to worry about, its just the way its programmed.

 

I did use the valley cover bolts... I'll pull it off this weekend and see if I can find the problem.