No oil passes thru the upper intake, so that's a strange place to see oil leaking. Are you sure he wasn't pointing toward the lower intake (the seam between the intake and the cylinder head) or the valve cover? Another common oil leak on 3.1's is the oil pump drive shaft o-ring. It's basically a distributor with the top cut off that goes down in the center of the "V", drivers side, under the throttle body. It's a fairly simple and cheap fix, the 3 required gaskets cost less than $10 total, and it takes about an hour to change.