I have a 91 4.0 Explorer and I can't find the gas filter. I have been hunting but as a big guy it's hard to get under there to see. Any help would be appreciated.

Its under there somewhere on the inside of the frame rail this might help:

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/0b/86/57/0900823d800b8657.jsp