Holley sniper EFI motor suddenly revving uncontrollably when I blip the throttle

It won't do it until the motor is up to temperature, but at that point when I blip the throttle off idle hard enough it will stay at high rpm and will not return to idle.
This is system that has run normally for over a year. I am being told to check for vacuum leak, but I have no smoke tester. Been racing this combo for almost a year now and it has never done this before.
Gen3 hemi 414 stroker with mopar drag pak intake and Holley Sniper 4500 Throttle body Fuel injection.