1991 Dodge Stealth Drove Car Home Next Morning Would Start 5 Seconds Die Over

I drove my car home the next morning it would start for 5 seconds the die over and over it will run good in the 5 sec I was told it was an ecu. I replaced it it ran good I let it sit and idel it died after7 mins it won't start now it has no fire at the coil to the wire and its all I also ck the injectors wit the test lite and I got nothing. Thinks so much. For any help!!! Its going to be a dirttrack racecar so I realy care less if its on switches