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

RockinRobin said
EFI systems use a combination of data to determine how much fuel to put in: water temp, air temp, A/F ratio from o2 sensor, etc.

I take that as a "yes". That's worse than some of these congressional answers I've heard.

I would check the resistance on that temp sensor. From the sound of it, you'll need to to it while it's up to operating temp.