So, after driving the Jeep around the weekend before last and last week, in preparation for a trail run on Saturday, it seemed all my problems were gone. but then, on Friday, I got a CEL. Put the code scanner on there, and it had 3 codes; sustained lean mixture, sustained rich mixture, and voltage from O2 sensor off scale. I reset the codes, but the lean mixture one kept coming back. I suspect the newly installed O2 sensor is not up to par, as, aside from high fuel consumption, the Jeep is actually working fine, so I will try to change it. Also, the oil pressure seems high, and that sensor was replaced recently as well. It just ticks me off that this thing can never have EVERYTHING working well at once! Anyway, I just wanted to rant and vent my frustration! I'll let you know if a new O2 sensor cures the problem... Oh, and, of course, my Cruise Control is not working either! but at least the Jeep is running well!