Have the dealer try re-torqing the bolts first and rule out if its just a simple throttle body gasket.
sounds like we are all in for future problems.
Why doesn't someone make a metal upper intake.
Thay are sure to get rich!

Thank you Karfreek, glad to see more information on the intake manifold nightmare.
Silver have you changed the lower intake manifold yet? The EGR tube sticking up from the stock lower manifold is ¾ inch OD and causes the upper plastic manifold to warp or burn through. In the new lower manifold the EGR tube is smaller, rumored to be 5/8 inch OD, so the tube is not against the plastic.
Do not know why GM did not use a smaller tube OD the the hole in the EGR is only .390 inch ID.

Glad I could help and arm you with info to take to the dealer. 8k is unheard of for failure.

My B'ville is Supercharged but my wifes Grand Prix is N/A and I track intake failures all the time on the net. Hers is a 99 with the Delphi manifold and no failure yet, but any day Im waiting for her to tell me the coolant light came on. She is 500mi from 70k.

Jay

Jay....

I did my UIM on my 99 at 77K this past summer. The original Delphi intake was 100% intact and looked brand new (except for some carbon build up near the throttle body). The really disappointing part were the lower intake gaskets. They were severely degraded. Even though the UIM may look OK, don't discount what'* undiscovered under that lower intake manifold.