So you have spark. When you say you have fuel, do you mean fuel is coming out of the injector? A chunk of gunk when changing the injector or messing with the fuel system could have clogged it.
Beyond that I’d probably check compression. Unlikely the problem, but a quick and easy thing to check. I’d also wonder about the idle air controller.
680 Camo Rincon, Warn XT30, ATV Guru bumper, Mad Dog bag.
500 Foreman, Warn 2.5.
Rides in 30' Patio Hauler 5th wheel. Towed by 3500 SRW Ram.