Three things all internal combustion motors need to run, air, fuel and spark, or heat like diesel motors use, to ignite the fuel You've eliminated the lack of fuel so we all know the air is still here so what is left
AKA, use the process of elimination to find where the electrical problems is now Do you owned and know how to use a Volt Ohm meter? If not buy one and learn how use it, you will be glad you did
Another good thing to have is a wiring schematic or diagram for your car so you can check the voltage at each connection Most mopars have a firewall junction block that can cause problems on the wiring harnesses in the engine compartment and under the dash
I will bet money or donuts on a loose or corroded connection in the ignition feed circuit, it is going open or high restance when heated up