F-150 won't run

I have a 5.0L, ‘86 F150 with 90,000 miles but prior to my recent purchase the engine had been replaced and the vehicle has an electronic fuel injection system rather than a carburetor. Recently the truck died while sitting at a red light and I’ve not been able to get it restarted. The engine will turn over but immediately dies. I’ve confirmed there is fuel to the injectors and there is a spark from the plugs. I replaced the ignition module and fuel pump. I don’t know where to look next.