Very muc
Very much the trouble associate with temperature. The 1st ecu seem fine, the problem could be weak fuel supply at hot temperature, or spark cut off because high temp changing sensor structure.
Do this. Put the 1st ecu back, drive it until hot. Turn off and start. When it won't run spray starting fluid through intake. If if run: the problem is fuel supply. If if won't run: no spark. At this step, check crankshaft and camshaft sensors. Possibly your engine temperature higher than factory expected operating temperature, that distort crank/cam sensors (or whatever sensor relate to ignition )
Only guessing like what I would do if I have the same car. I'm not familiar with 5.7 hemi.
