I need to replace my intake manifold, i picked up one from a junk yard for my lo3 tbi, it has had a small crack at the front edge above the water pump for about three years. it barely leaks a quart or so every four months & stop leak didnt work. i also believe i have excess carbon buildup, although i used sea foam, & tried to clean out the egr intake ports. when i take off the egr valve & plug the exhaust side, the suction side used to suck & idle high, but now it doesnt suck at all, i cleaned out the carbon as much as i could get to, so i know the egr isnt working, & it sets the code, but the car runs great. my question is, what besides the intake gasket do i need, & can someone tell me how i need to use silicone going up the sides of the heads to complete the seal. this will be my first intake removal.

 

Intake gaskets are easy to change.
Be sure to lay a big towl inside the engine while you are cleaning everything so you don't get any crap in the engine.
With the aluminum intakes I use the Victor gaskets you get at Napa.
They are a little thicker then Felpro's and seal really well.
Put a little silicone around the heads at the front and back where the water flows thru and a little silicone on the gasket too after you put them on.
Those little rubber gaskets they give you in the kit for the front and back of the block, throw them away. Take a center puch and make a nice row of sharp dents on the block so the silicone has something extra to bite into.
I use the black "right stuff" silicone here and lay down a nice 1/4" bead on the front and back being sure to get a nice amount right in the corners.
Put it together and enjoy. Be sure to torque the bolts in a spiral pattern starting from the center. I think 30lbs is the amount to tighten them, but I have always just cranked down good and have had no trouble.
Hope this helps.