Unless I learn something else that's where I plan to go with mine next week after the holiday.I just picked up a 2006 Magnum R/T with the same issue. Really surprised this is so hard to figure out given the age of these cars, frequency of the issue, and the fact that there is a forum community out there. ( If there was a definitive post on this / FAQ etc I missed it)
I am planning on trying to get a 2007 PCM/ECM core i purchased to get reworked for my 2006. Some say this wont work but I don't see why it would not work....Seems like they changed the design for the PCM without changing the rest of the car..... and I'm guessing it was due to all the trouble they were experiencing since the car was not redesigned until 2008.
From what I have read I think Solo in FL might be a good place to try for a refurb.
Solo PCMS PCM ECM ECU Engine Auto Computers
Solo PCMS is a provider of PCM, ECM, ECU, and Engine Auto Computers
I had this problem for years.
I had exact same car and LOVED it for my dogs. Had to relegate it to secondary use when this became an issue at about 90k miles.
There is a box under the cowl on passenger side, when I removed connector, cleaned it and added dielectric grease the situation became rare.
In emergency (at highway speed, you CAN reset computer... CAREFULLY and in this EXACT order. push shifter to neutral, crack driver door, QUICKLY cycle key off then back to RUN (regain steering), start car then shut door.
The PCM doesn't restart unless key is briefly off and a door opened.