I have a 2006 TC with a few miles on it (220k) and I am getting a little bit of a delay when I change from accelerating to decelerating and likewise decel. to accel. It happens every time, but the car runs smooth all of the time other than when I change. I have tried adding fuel-injection cleaner for a couple of rounds but it doesn't seem to do anything. Any ideas?

 

How is there a delay from accleration to deceleration? Like the throttle is still open and the car is still pulling? The moment you take your foot off the throttle pedal, it should start engine breaking.

anyway, clean the throttle body and MAF sensor. Might be getting stuck.