I have my afr at around 13 at idle. It seems to stay on without too much work on cold startup and doesn't dip the rpms too much when I slam the throttle closed after a good blast (stick car). I have a Holley main body with no choke so I have to pulse the acc. pump for a few seconds then hold it at 2000 for 30 seconds then give it a minute at 1200 to warm up before I trust it not to stall. I usually just do that then drive gently for a bit