My car has recently developed a weird idle when the car has been sitting over night or all day at work when you start it cold. It starts fine then about 5 seconds later starts to act like it is misfiring (buck and studder/ shake) when the air pump is activating, this lasts for about 5-10 seconds then smooths out to a normal idle. There have never been any cel codes and it doesn't affect drivability at all. Does anybody have any idea what it could be causing this?
