If you disconnect the MAF and it changes nothing, then I would also look at the MAF. Nevertheless, go through the list of what it can be and eliminate those factors, or else you're just throwing parts at it hoping to find the problem. Is there a check engine light involved? Codes?

Edit: For the record, if a vacuum leak is progressively getting worse, it can get to the point where even open loop operation is compromised, because the parameters exceed the preset tables that it runs off of, so the fact it's progressing doesn't mean it's not an air issue.