My 2011 CC EXecutive has lost the power and responsiveness that led me to buy it in the first place. Car used to respond when I hit the pedal while in motion, now it struggles to rev past 4,000 RPM and it definitely doesn't accelerate anywhere near like it used to. It's been doing this for about 6 months, however every 2-3 weeks it runs great, but only as long as it's running. Once I shut it off and re-start it, ugh, the problem is back. I just had an air/fuel induction service and also had carbon removed from the intake manifold with no improvement. VW dealer says it's running "according to spec", no codes at all, they have given up. Help!!!