Sounds like there is a problem with the oil pump itself, dirty oil, or some kind of contaminant to spin the bearings. These little 2.4s are pretty durable, what with the bottom end having a cradle for the main bearings and all, I would think getting a short block bottom end and cleaning the head would probably be cheaper than a whole engine ( unless you find that low miles couple hundred dollar pull it yourself engine, but then you wouldn't know its history), and go from there. I looked at the rockauto.com site and the bearings and gaskets are the same for the 2.4 blocks 2003-2008, it is a matter of the correct pistons for the PT head and then the location of the crank sensor (your PT head would have the cam sensor), the master rebuild kit with oil pump, timing belt, rings, bearings (rods and mains), freeze plugs, and gaskets is $497. So, if you could find a known good block for less, that's the benchmark. Some real online investigations of changes and updates done year to year may be able to tell you some of the differences, things like Road and Track or actual Mopar tech articles, could tell you if a sensor was changed, improved seals, smog improvements, things like that. Bottom end-wise, unless there is a change like this, the short block should work without an issue.