I can not solve the issue I'm having on my 2010 mk skoda octavia vrs. Engine code CCZA. When starting the car from cold I have a bad missfire and really rough idle where the car will cut out if I don't get it moving quickly. Once the car is warm its fine. I have so far had spark plugs and ignition coils changed due to engine codes pointing at missfire in cylinder 3 and 4. This made no difference, there's no vacuum leaks pcv has been checked and is fine. I then thought it might be carbon build up on intake due to short journeys I make so had the inlet walnut shell blasted and all four injectors were changed but still no help. The only other thing I have noticed is an oil build up on top of the gear box but don't know if this is connected. I am almost ready to give up and get rid of the car which is a shame as it only has 66000 miles on and has been looked after. Any help or advice would be really appreciated.