This is my first post!
I have had a stutter on my Z30DT (105 000 m), as described by many, for a few years now. Recently I had to replace the SCV. I have now also finally done every replacement and clean up I can think of (SCV, EGR, MAF, MAP, cleaned DPF, cleaned fuel tank and lines, cleaned inlet manifold and throttle housing) and my automatic Vectra-C goes brilliantly, EXCEPT when I release the foot pedal to stop acceleration. There is a cough before hitting a steady speed. This can occasionally occur while driving on a flat road - presumably when I lift my foot off the pedal ever so slightly.
Please, can someone help to diagnose? I have an OPCOM but no more error codes are appearing.