Need help diagnosis 2002 LS V8

[HMass1]

Just replaced the valve cover gaskets, starter, and alternator and when I started the vehicle I noticed a hissing as if a hose was off but I checked multiple times and all are fine to the eye. No dash lights are on and the car is spuddering at idle. Shut off once but not again. Drives without issues but man that hissing and bouncing at idle is just ridiculous any help is appreciated. I have a video recorded that I would like to post but I don't think I'm doing this right lol

 

[joegr]

Did you really replace the head gaskets (remove valve covers, remove front of engine, remove manifolds, remove timing chains, remove heads, ...) or are you really just talking about changing the valve cover gaskets? If it's the latter, then you probably have a cracked PCV tube.

 

[HMass1]

I meant valve cover gaskets, pardon me, I was in a rush to post on here

 

[HMass1]

Did you really replace the head gaskets (remove valve covers, remove front of engine, remove manifolds, remove timing chains, remove heads, ...) or are you really just talking about changing the valve cover gaskets? If it's the latter, then you probably have a cracked PCV tube.

Joe are there any hoses that connect to the rear of the valve cover on either side? My brother helped take it out but hasn't been back since and it's very hard to see back there.

 

[joegr]

Not that I recall, but there are hoses/tube back there connected to the intake. One of them might have been damaged getting the cover out or in.