Replaced intake manifold on built 2016 golf R after it cracked. Now the car has a rough idle

[Uffda]

Hey all!

I had my intake manifold crack on me after installing my second fuel rail. The APR intake mounting area just blew out. This caused the car to shoot fuel out. So I was lucky it did not catch fire.
Had it towed and my pro shop replaced the Intake Manifold with a new one. They test drove it after and said it runs great.

I drove it home and got it on the free way a bit...and pulled off and when I went into neutral the car started sputtering a bit...rough idle. If I have it in drive it's fine. Sport mode no difference.
I have a pretty built car...Borg Warner APR Turbo with a ton of custom work including a Precision Raceworks fuel rail and 1350 CC injectors. The new intake manifold uses the heat brackets as opposed to the APR injector mounts I had in it before.

I'm not sure what the deal is but I'm going to take it back in perhaps tomorrow. My assumption is that the car needs to relearn its idle again after the intake got replaced and it was run a bit with the cracked manifold.
I pulled over like within in 2 mins of the car sputtering and the fuel leak a few days ago.

Cause?

Injector gaskets or leak?
Boost leak?

I do see the car at idle bouncing on the boost gauge a bit when it sputters in the negative range like it's sucking air in or something.

I can post pictures of the cracked intake manifold and the cap off and the after if yal want

Eric

 

[jimlloyd40]

Vacuum leak?

 

[Uffda]

We shall see! Thank you sir.

 

[farcyde11gti]

Listen for whistles/hisses around the top end. You can spray engine safe cleaner that makes bubbles around junctions if you think you have it narrowed down. Having someone rev the car a little helps if the throttle blade isn't accessible, I find.

 

[Navi]

could be a leak, but i remember on other cars, you have to do a learn process for when you change intake manifolds. Is it the same for VW? Might want to look into that.