This is a great site. Just joined Saturday, and after scanning only the last 15 pages of posts, looking for ideas, found my answer. I was getting the various codes relating to O2 sensors, etc, but wasn't convinced that was the problem. Went to Auto Zone, as before, and the little boy clerk used their OBD scanner on my Sport Trac, and based on their conclusion, ended up buying a new air filter (K&N this time), and fuel line filter. It was about time anyway, so no loss. Nope, no good, still got the codes and rough idle. Soooooo, bought my own OBD scanner, then went through this site, found several posts regarding a rubber 90 degree elbow at the front of the engine, connected to a plastic pipe going to the back of the engine. Once I focused my attention in this area, the hiss of vacuum leak lead me right to the rubber elbow. The hole was about a quarter inch, and collapsing from the vacuum. This was Sunday, with no dealers open. Auto Zone proved usefull this time with a multi angled rubber hose, which I cut to the right 90 degree angle, and made the repair. Runs like it did before my Christmas trip that started all this, like new! Sounds like this is a fairly common problem, and the only reason I'm going into a detailed description is to hopefully help any other new users. These forums are great! Thanks.
