I actually had my car do exactly this when it was new to me... I was showing off with some passengers, hit pedal to the metal, and it went at first but then DIED. Literally zero power. I eased off the gas, then gently applied the gas, and it was fine. I can't say it was due to traction loss, but I do believe for whatever reason the car was designed to do that under certain conditions... like the "limp home mode". It's been 20,000 miles and many drag races since, and it's never reoccurred. It could also be rev hang if you let up when the RPMs were very near the max (search the forum for that one) as I've noticed when in rev hang the throttle doesn't respond as expected... but only for a second. My wife's Escape's Ecoboost does the same exact thing. It's a very peculiar sensation.