Engine Stumbles Cuts Out while driving
 

2006 Dodge Magnum RT 5.7Hemi RWD 157000 Engine replaced at 108000

Car has started to 'stumble' while driving. It stops running momentarily and kicks back to running. Sometimes it will keep doing it, sometimes it will run fine. Sometimes it stumbles harder and may stall. Putting it into N and restarting usually it will go on running fine.
Friday morning it stumbled and died and wouldn't restart. I had to move to the side of the road. It started and died several times, then started and idled and died when I put in drive. Then it started and I was able to drive it normally.
Usually when it stumbles or dies, the radio resets to defaults.
Sometimes when it stumbles, the ESP/ABS warning light will come on. If the light stays on, the car will usually run fine thereafter.
It usually happens driving flat and level and steady driving.
It happens at all fuel levels regardless of time since filling up.
When it runs, it runs fine, it is only this stumbling and cutting out that is the problem.
Occasionally, it will just stop running while idling. Usually, it occurs after driving for at least 5-10 minutes or more.
No codes from key method.

Any ideas?