When you replace the intake gaskets, have everything in place, then hand tighten all the intake bolts but do not tighten down. Tighten down the long bolt that pulls the intake up against the timing cover first, then the intake bolts in the proper sequence. Won't hurt to put a small coat of silicon sealant around the mating surface of the timing cover/intake passage surface, just a little to ensure a good seal, let cure overnight for best results. This is a common problem on Pontiac engines. Hope this helps you solve your problem!
