Fuelpump pumps up, injector doesn't work

My 92 s10 sometimes starts but mostly doesn't. The fuel pump pumps up and stops like it should,but my injector doesn't work. I dont know where the injector relay is located but I think this would be the place to start. Does anyone know it's location? Thanks!!!:banghead:

I don't think there's an injector relay, I believe it's powered by the computer.
Is the check engine light on?
A fuel pressure check would give even more information.
Does your truck have a round or rectangular air filter?