You're dealing with a single cylinder misfire. The shudder you're experiencing on take-off and rough running sounds like ignition misfire. You know it's cylinder #5 so start swapping ignition components with a known good cylinder. Clear codes...when the symptom/problem recurs see where the code is. If it's still #5 think mechanical,if it moves to the cylinder you moved components to....you have found the problem. Good luck!