15 year Ford senior master tech, I second the egr cooler. However since you are out of warr. I would suggest looking into either an egr cooler block off plate or delete pipe. Because replacing the bad one with a factory one will result in it going bad again. Also when teh egr cooler goes bad it severly restricts coolant flow to the oil cooler. When that goes bad you get oil in the coolant which is a beotch to clean out.
The downside is it will obviously not be emmisions compliant anymore and it will set a check engine light. Although you can get a tuner to turn it off.