cylinder 6 not contributing, please help

[rockbound]

I have a 99 7.3 with 170k miles on it.

started running rough, missing, and loss of power.

Through a cylinder 6 not contributing code.

i replaced all the injectors and still having the same issue, and still throwing the same code??

what else should i check?

cps? wires under the valve cover??

what else??

thanks

[ELT]

Cange the valve cover gasket and wiring harness.