Haven't heard this term in long time. Flat Spot is what we used to call it when there was a brief moment when the power just was there. My 2012 Shelby GT500 has such a condition while accelerating in second gear. At about 45 to 50 MPH there seems to be not a loss of power but a very short no power gain. If I was timing it, it would be for about 1 second or less. I use 98 octane. The car has 12,000 miles on it and seems to run great otherwise.