After replacing valve cover gasket and plugs coil packs not firing

What cylinders are not firing now?

Clearly it seems as though there is still something unhooked as doing either of those repairs should not cause an issue on the coils. Have you checked to see if the coils are firing at all or is there a chance you plugged the wrong connector into one of the coils? Which would cause it to fire but not at the right time.

Let me know what cylinders and double check your connectors even though these coil on plug harnesses usually don't have enough slack to plug it into the wrong coil.