94-s-10 acts like it's only on three

I have an 94 S-10 blazer. I just replaced the plugs,cap,and rotor, I also replaced the egr,map,tps,and the tpi(unit inside the manifold) anyways I get no codes any more but it seems like it is only running on 3 cylinders. Could it be the ignition module? or what? thanks

double check that all plug wires are routed properly and going to the correct cylinder.