what is the cause of a Vacuum leak?
start the car up, and get a can of starter fluid, or propane, spray the areas around the intake and the thottle body, if the idle picks up, then dies down, you got a leak. make sure you spray where the intake meets the heads.
Why didn't you just bump this thread??
https://ls1tech.com/forums/generation-iii-external-engine/517314-ls6-intake-now-noise.html
You have to find exactly where it's leaking before you can fix it. I'm going to bet you still have the factory LS1 coolant pipe instead of an LS6 unit like you need and the intake is not sitting flush with the heads.
Here's the artical on how to do it.
http://ls1howto.com/index.php?article=5
In this pic, you'll see a metal tube connecting the heads, and running across the valley cover between them towards the back of the block. The 2 black circle things you see are the knock sensors. This big pipe that runs across MUST be removed, or the LS6 intake will not sit down all the way. There is also some clips holding the knock sensor wires to the coolant tube which will stop it as well, they can be untaped and removed.
If you look below your TB and see a hard metal line connecting the heads that runs UNDER the intake manifold and toward the back of the car, you'll need to pull the manifold and replace it with the correct stuff.
https://ls1tech.com/forums/generation-iii-external-engine/517314-ls6-intake-now-noise.html
You have to find exactly where it's leaking before you can fix it. I'm going to bet you still have the factory LS1 coolant pipe instead of an LS6 unit like you need and the intake is not sitting flush with the heads.
Here's the artical on how to do it.
http://ls1howto.com/index.php?article=5
In this pic, you'll see a metal tube connecting the heads, and running across the valley cover between them towards the back of the block. The 2 black circle things you see are the knock sensors. This big pipe that runs across MUST be removed, or the LS6 intake will not sit down all the way. There is also some clips holding the knock sensor wires to the coolant tube which will stop it as well, they can be untaped and removed.
If you look below your TB and see a hard metal line connecting the heads that runs UNDER the intake manifold and toward the back of the car, you'll need to pull the manifold and replace it with the correct stuff.
