91 6000 3.1 no injector spark

ok i have a 91 pontiac 6000 3.1L and the car starts and after about 30mins it dies on me. So we replaced the igniton mod, all the coils, CP sensor... and now we tested the injectors and it getting weak to no spark. So the fuel pressure is good so now im not sure what else to do. BTW the spark plugs are good... all fluid ok so any ideas?