Why is my 95 pontiac sunfire not staying running after changing o rings in the fuel injectors?

I replaced the o rings in the fuel injectors on my car cause they were leaking. Now the car won%26#039;t stay running. It cranks up and has spark. But just dies on me. I checked the fuses. Fuel pumps works great. I also checked the electrical to. Its fine. Does anyone have any suggestions for me? Thanks.|||check fuel pressure as well as injector electrical connections. Are they in correct order?