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

Two things to consider, re-centering the blades if they’re rubbing, or putting an extra wind in a worn out spring on the secondaries:

Re-centering:


Winding an extra turn into the secondaries:


Edit:
I guess I should say, check the throttle bores for cleanliness/rubbing first. But I’m wondering if the issue is heat/thermal expansion related of the bores vs plates, which leans toward the re-centering solution…get it warmed up and check then since that seems to be when your issue appears. Then it might be trying to re-center when the throttle body is warm…