P0300 post intake gasket

[Chvy_03Tahoe]

Hello,

I'm hopeful someone can guide me. I just went through the installation of a new intake manifold gasket (I used the new Delco gasket). When I buttoned everything up and started my Tahoe, the engine ran super rough and through P0300, 1) Engine Misfire, 2) Engine Misfire. I've looked at everything I can come up with, including removing and reinstalling the gaskets multiple times (and once, even the old gasket just to see). Every time I start up the Tahoe, I get the same rough running and P0300 code.

I'm really stuck and need some help, Please...

Any advice, simple or not would be greatly appreciated. Thank you in advance!

 

[ezdaar]

Check for cracked Pcv tubing.
Make sure you plugged all connectors in.