ok my car has a missfire in cylinder 3 at idle and under load i changed the plugs the wires the cap and the rotor i tested the cylinder and it is getting spark i did a compression test and topped out my 300 psi gauge in all 4 cylinders with the engine cold i pulled all the plugs and the 3 that were running rite looked fine and the one that has the missfire was dark black for some reason iam stumped what could cause all the cylinders to work except cylinder 3 please help ??

 

heres my setup up if it will help u out ls bottom end, ctr pistons, gsr head, skunk 2 manifold, str tb, rc 310 injectors, skunk 2 stage one cams, intake, dc sports 4-1 header, 2 and a half inch exhaust no cat, P03 ecu and a vafc2