Dealers are essentially being forced by Chrysler not to condemn engines for consumption and warranty replacement. There's not way that kibd of consumption is "normal". Some 2008s were assembled incorrectly by the Mexican engine plant, but by now most of those should have been cycled. The ongoing issue with the 3.8L seems to be a byproduct of the 5w-20 oil spec. To wit, some techs suggest the 5w-20 burns off, causes the PCV valve to stick open slightly, drawing more oil into the plenum than normal. The oil burns off causing the rings to become inefficient, etc., etc. round & round we go. Step one, replace the PCV valve with one of the newer design, or an aftermarket piece. (Chrysler has superseded the earlier part number.) Step two, run a Seafoam treatment through the intake to clear the oil based carbon off the valves, the top of the pistons and loosen the rings. Step 3, change the oil and filter and use 5w-30 or even 10w-30. Some guys have even said they use a diesel spe. 10w-40 and have had great success.
Mine ('09 JKRU) started to consume a bit of oil at around 10k. I switched to 5w-30 at that point and now at 35k the consumption is extremely small, maybe 1/4 qt in 3k miles.