Happened to me last couple months in my 2003 Grand Caravan. My original PCM had a short that caused the van to die and stall at random times. Had a new PCM installed for $800. But less than a week later it started happening again on top of the shifting issues that you described. I decided to just sell the van and get a 2011. But I would suggest you try and find if there's a reason for the bad PCM. In my case, there was a voltage spike which shorted one of the circuits; if I had kept the van I would have tried to track down why it shorted.
My problems also came with several oxygen sensor codes, so in my case I would have figured a shortage in the heater sensor wires/circuits.
2011 Chrysler Town & Country Touring | 2008 Toyota Camry Hybrid | 2002 Jaguar X-Type 2.5 AWD | 2003 Yamaha V-Star 650 Classic