The oiled filter itself is the most common false MAF reading contributor. The oil tends to deposit itself on the MAF wires, and make them read false. I would start by cleaning the MAF, and then looking for a source of unmetered air, ie. intake leak.
2001 Dark Highland Green Bullitt
12.25@110 naturally aspirated on a bone stock 2V longblock
Under Reconstruction for RS275 Drag Radial Class
Pushrods and Powerglide Coming Soon
If it weren't for physics and law enforcement, I'd be unstoppable.