Its a lot more simple than that, there are several settings that relate to idle, one of those is a vac setting below which the ecu will not control idle, idle also does not start to control til below 1300 rpm and 13 throttle setting (base is 10) so in moving the car and switching off and on the ecu opened the stepper motor twice for cold start, that set the idle outside the 1300 rpm limit and above the vac limit so it simply decided not to control, having warmed itself up a bit turning off then on caused the ecu to reset, as it now idled initially below the limit idle control worked.