I think this goes in here...
 

Another member of this forum recently made me aware of faulty upper intake manifolds on the 3800 series II L36 engine. Is this a big problem? Any way to fix it, or make the UIM last longer before it gives out? Also how hard is it to change the UIM and what can I expect to have to pay for one? Thanks in advance for all help.

Check it out:
http://www.bonnevilleclub.com/forum/...e=article&k=38

After you read that link. Please update your profile for your location. We have many members that have done this themselves and would not hesistate to help another member fix theirs. If we know where you are...we can offer our help.