Moderator - Please move to "Problem and Solutions" if this is a better fit there. Thanks.
I talked to my Ford dealer and purchased a cabin air filter for my '09 Escape. Here's some info regarding the install:
The Motorcraft P/N for the filter is FP-66. On the filter itself the p/n is 8L8Z-19N619-AB. The cost at my dealer was $24.95 before tax. The filter has a a piece of 1/2" foam around the filter held by double stick tape. Because of the foam, I don't think it would be easy to make your own filter and have it seal properly. The filter comes in a cardboard box that describes it as a "Pollen Filter".
The cabin filter enclosure is located on the passenger side in the engine compartment under the cowl. Here's how I replaced the filter:
Remove 4 left most plastic cowl pins with a phillips head screw driver and while pushing up on the pins from underneath. Once the pin is removed, also remove the fastening clip.
Hold upon the left side of the cowl and underneath is the filter enclosure. Unfasten the front clip which wasn't so easy, and then there's another one to the right that will also just pop out on its own when you try to lift up the cover. I used a bright flashlight to better see what was going on.
The filter enclosure has a screen so large items such as leaves and pine needles won't get through. The filter came with a small piece of single sided and double sided stick tape and very basic instructions. I didn't use the tapes.
The filter is marked "top" so you install the filter with the correct orientation. The filter enclosure and cover are flimsy and the whole arrangement is kind of lame and difficult to get at. If you look at the filter, and then where it supposed to go, you might have doubt that the FP-66 filter will fit properly. The filter doesn't fit exactly, but the foam takes up the gaps where needed.
While holding up the cowl and filter box cover, slide the filter in place through the small opening. You'll have to just feel around and gently apply pressure around the edges until you think it's seated. There's no good visible way to confirm if the filter is properly seated all the way around, so you'll just have to guess and apply pressure around the filter but not too much because the filter will crush slightly. After it's seated, just close everything up.
I suffer from grass alergies so I really needed the filter now. It's not a difficult job but for something that needs occasional replacement, Ford should have made this more user friendly.
Also, the WIX website shows a cabin filter for a 2009 Escape as a temporary p/n 49466, but shows it as unavailable. I called a WIX dealer and they confirmed what I saw online. Hope this helps you.