So i just bought a 96 Blazer 4x4, and it needed some work. I had a P0300 code so i changed it all, plugs, wires, cap rotor, pcv, air filter, fuel filter. Gave it a full tune-up. Now all i have is a P0303 code.

I have spark coming out of the wire.(that was checked with a different plug, not the new one i put in) I removed the spider injector to check that. I put 12 volts to the #3 injector and can hear it clicking just fine. It sounds like the rest of them because i checked them all.

I did not use AC Delco plugs because money is super tight but i know i should have. Do you think this could be the issue or could it be something else. I don't have a fuel pressure gauge or i would have checked that but i did hit the schrader valve on the line and i do have pressure, also all other 5 cyl hit just fine.

Also i pulled off the IAC. The plunger was very hard to push in and out, is this normal or does it need replaced too?

Any ideas would help, thanks in advance.

 

Have you done a compression test?

OBD-II Trouble Code: P0303 Cylinder 3 Three Misfire Detected