Random misfire

[Michael Hastings]

06 HD 2500 6.0, CEL GOES OUT WHILE UNDER LOADS. At idol  Cylinders 1,3,5 & occasionally 4 start to misfire. #1 has the highest misfire count and most actively misfiring followed by #5 than #3. Engine is at operational temp. Of 209dF. All injectors are new. Individually isolated all coils non are weak or dead and all plugs are firing wires are new MSD with metal boot caps ad original. Any help would be appreciated