remove cats or not
 

I have a 04 Edd. Bauer 5.4 expedition and looking for better mpg like everybody else is. I have a open air box, free low muffler and looking at 2 more ideas. Electric fans do they work on mpg as well as stated? and to remove the cats. Everybody I talked to so far as agreed that removing the cats will improve performance a lot, but some say it will improve mpg and others say it would hurt it. Eveninstalling the dummy o2 sensors will it help on mpg. Thanks in advance.