During my tune-up/alternator repair I pulled out my air filter (K&N) and washed & oiled it. While the airbox was open I had someone start the car then shut it off. The sneeze/chuff/pressure release sound came out of the intake with a little puff of air. Odd that it would start doing that now.
UPDATE: Now I have a dreaded "check engine" light. It's code PO174 (Bank 2 running lean). Coincidence? I've heard everything from K&N oil in the MAF to cracked intake manifold to intake manifold gasket/seal issues to "unsolvable" regarding this one. Anyone want to take a fresh shot at it? I suppose I'll start by pulling the intake manifold, checking it for cracks and reassembling with all new seals. If that doesn't work....