After making some adjustments to the Holleys on my 6 barrel I noticed that when I stand on it and then back off it doesn't come off throttle quick at all. Instead it seems to settle in on a fairly fast idle speed for a while keeping the car going instead of slowing it down. This only happens when I accelerate hard. The pedal seems to come back fine so I do not believe the plates are staying open. Not sure what's going on. Any help would be appreciated.