When you pull the intake off and inspect the gasket, if you can see any places where the black coating is chipped away and you can see shiny metal, you need to replace the gasket.
I didnt replace my gasket and it had a single minor chip in it and it caused major idle problems.
IIRC, id just replace it anyway. The gaskets are under 30 bucks for the intake set and you can refresh all the gaskets in your intake.