i have code p0304, how to fix it ? on 2003 Chevrolet S10

i had good compression, good spark. i replaced : new ignition coils spark plugs and wires

2 answers
Check for a vaccum leak near # 4 cyl. Check for injector pulse and fuel also. IF you have all that stuff you stated.
How much compression did you get (psi) ?
sounds like an inj issue or pulse signal at inj.