These engines will run on 4 cylinders. My daughter sprung a leak on fuel line to #5 several years ago. Couldn't fgure out where the leak came from, diagnosing long diwstance, so she drove from Lexington, Ky to Richmond, Virginia with the leak. Got real slow going up some of the WV grades.
Long and short, if the lines are not properly secured with the plastic brackets THEY WILL FRACTURE.
And, yes, replacement lines are available from the dealer at very reasonable cost. I would not go the route you have chosen. I recommentd getting a new replacement line for which ever cylinder yours failed, and get the plastic brackets as well.
As for your knocking, you could isolate each cylinder to determine which is knocking by loosening the fuel line at the top of the injector, one at a time, listen for canghe, retighten and move on to the next, until you find the cylinder that is knocking.
I can't tell you what to do after you isolate the cylinder other than to change out the injector with a spare, if you have one,to see what happens.