Thanks for the suggestions!
I cleaned the MAF and checked for obvious leak/tightened the worm clamp.
What is the best way to check for leak? I was thinking about disconnecting the big hose after the MAF and pressurizing it. That part of the intake is not normally presurized, can I damage something? Or is there a better way?
Is there something in particular that I should look at in the Access Port to help pinpoint the problem?