i have a 99 ls with a b20 recently my check engine light came on it was a random misfire code and also misfire cylinder 1 and 3 but it doesnt miss fire mechanically i changed the distributor and new cap and rotor still the same.....any ideas? im hoping its not wiring thanx guys

 

well it turned out to be the injectors but now i have a lean code p0170 171 and its driving me mad changed o2 didnt do anything bumped up fuel pressure to 50 psi and still code changed fuel pump, fuel filter....i still got it and today i got a p0420 which is the cat so i dont know what to do now :/