I had that issue once in one of my Chargers under hard acceleration once in a great while it would just cut out like you turned off the ignition. It turned out to be the bulkhead connector in the firewall. Engine torque must have pulled on the engine harness just enough to cause the issue. Once I figured it out pulled everything apart, cleaned all of the connections, dielectric greased all of the connections & put it back together. Been good ever since.