x type cruise not available
 

Thought I had curred the cruise not avail measage checked all hoses and swapped the throttle body, and new battery and no problem for the last 2 months ...did 250 miles yesterday perfect and stopped in service area .. on re joining the motorwayaccelorating up to 70 the jerking came back just as if you were turning the ignition on and off then it goes away, if you lift off and apply the throttle again it might do it 3 times but not always there is no missing like fuel starvation or plugs misfiring it just goes dead and as quickly back to normal just as if a wire has come off.
Did a further 250 miles happened only twice till slowed down on country lanes and had to change down to 1 st gear and then did it again in 1st 2 nd and 3rd then all ok again ??? Left overnight been out in it today no jerking .
Always starts first time never misses, coughs or stutters.
Have thought about the fly by wire throttle actually on the pedal as happens on gentle throttle movements anybody any clues?