Ok. This is what I have going on now, I can run the engine to WOT and when I bring it down to idle some times it will stay at a fast idle for maybe a 20 seconds and sometimes longer before falling to a slow Idle. I tried adjusting the low end but I'm not sure what to really do. The transition is good and the high end is good. Is this a tuning problem or maybe an air leak? or something else. Thanks for any help.