Engine control lamp lights up while waiting at traffic light

Hello dear ones, my Omi is a 2.0 XEV 136PS got a set of new ignition cables a week ago, because the old ones had sparked and my Omi had thus jerked. Problem perfectly fixed. One week later the following problem: Idle is about 700U/min consumption ABNORMAL is low according to the on-board computer: 0.5L/h Always in the stand (not every time, but sometimes too/frequently) e.g. when waiting at the traffic light lights up the engine control lamp. When starting after about 10m it then extinguishes again and Since the new ignition calves and since the warm temperatures have a significantly lower consumption: 50kmh -> 4,5l/100km What could this be about with the MKL? I used search function, unfortunately found nothing. Thanks in advance. Greetings