VW Tiguan 2010 misfire

Started with cylinder 1 misfire code about 6
months ago on tiguan. Could feel it "misfire" when
driving. Replaced spark plug for cyl. 1 .... did not
help. Replaced cyln. 1 coil.... could feel somewhat
of a difference but engine light still on.  .....then
EPC light comes on....
Flash forward..... over 6 months we have taken it to
5 mechanics... changed the pcv valve 2x....
changed the fuel injector on cylinder 1...  changed
all spark plugs and coils, had walnut blast for
carbon build up by dealership.....  and still EPC light
is on and engine light is flashing. Car shakes bad
when u start it or try to drive it!!!! I am at a real loss
.... I had compression teat done when fuel injectors
were changed and mechanic said no issue... ( that
was before DE carb....not sure if that means
anything)  I have asked dealership to look at timing
chain due to resent lawsuit .. but they say it will
cost over $1000  to tear it down to look at it. ...  
Just don't know what to do next.... any help ??