93 ex coupe runs for 20 seconds

I bought this civic cheap cause it had old gas run through it. I've replaced the fuel, filter, injectors, main relay, vacuum advanced, IAC valve,(also water pump and timing belt although probably unrelated) and last but not least my ECU. Now car will crank and idle for 20-30 seconds then die. Any suggestions?:disappoin

it sounds like your coil or igniter in the distributor.. next time she dies see iff there is spark..