Audi Repair: Engine vibration/shudder when idling, engine vibration, timing belt

Question
My Audi A6Q is 65000 miles. Replaced spark plugs and ignition wires two years ago. Replaced timing belt, water pump,thermostat, cam seals, engine mount and cam adjuster seals 6 months ago. The misfire happened at cylinder 5 two weeks ago. Technician remove malfunction code,but now the engine still a little vibrate and shudder when it is idling. Any issue cause like as spark plug, ignition wire, ignition coil or something else.Your help will be highly appreciated.

Answer
HELLO
looks like you have done everything to maintain your car.
You may have bad or clogged injector which is not spraying the way it has to. The cheapest way to check this is swapping injectors . #5 to #4 or #6 and see if the misfire moves to next cylinder. If you can use VAG you can see misfires while the car is running. (go to value blocks #15
and #16 . 15 is for cyl. 1,2 and 3 , 16 is for cyl. 4,5 and 6.
good luck               pltech