When at operating temperature engine stutters, shuts off and will not restart

It will start and run, when it warms up to operating temperate you have to hit the gas and it stutters and shuts off and refuses to start again. It is dumping gas in number one cylinder and fouling out plugs. I cannot get it to scan. I hook up my code reader and it says it cannot connect to ECM. I cant get it to restart and it has continue this to me. I clean fuel lines out and changed coil pack along with ignition switch. New fuel filter, check wiring and everything I can think of and it keeps doing it. I am thinking it could be then ECM, but I am unsure. My girl had to jump it one day and crossed the jumper cables and now positive to negative and negative to positive. Ever sense then it has not been running correctly. It will start then when the engine gets to operating temperature I go to give it gas it back fires and stutters, shuts off and smells of fuel. And will not start no matter what. I have to wait over night and then try again and it starts and runs but repeats the same thing. I am thinking it has fried the ECM in the car. I tested the #15 pin on the ECM wiring and it is getting less that a volt of power to it, like 0.54 of volt. I cleaned all the grounds, check everything I can. I do not know what is going on here, besides the ECM. Is there any idea what this could be? Please help this car is used to help support my family. Please help me thank you.