Engine movement could be a simple as a mount worn. Dogbone mount causes movement but your gearstick would move abit during acceleration.
My passat ticks over at 858 according to the live data taken the other day.
If you have a scanner, best thing to so is.scan when it cuts out as it may have the code there, crank sensor for instance but as soon as it rums again the codes gone because its not a perminent fault