imma go out on a limb and see if a supra/lexus guy has had a similar problem....

I have a 98 GS300 2jz-ge I6. I have a misfire on cylinder 4 and I cannot locate the problem. Coil, plug wires, plugs and valve cover gaskets have been replaced. For those who dont know #4, # 2, and #6 are coil on plug. I have moved the three coils and plugs around to different locations but the problem persists on #4. any suggestions or input would be cool... before I tear into the harness?