I re-read your earlier posting, and have the following questions:
1) at what revolutions does the problem occur? Assuming something reasonable that will not trigger the transmission downshift logic, say around 2500, try using manual shift mode and see if it happens in all gears once you reach the critical revolutions or only in some. Also try it with the car in neutral, at the same engine revolutions: can you still hear/feel the clicks, even though the car is not moving?
2) Temperature: does it happen regardless of engine temperature? outside temperature?
3) How many miles when you first noticed it? How many now?
4) brand and type of tires?
5) When it happens, does the car actually lose momentum, however momentarily, or is the click-pause-click more of an engine revolutions variation?
6) When the problem happens, what's the duration? is it in the order of a fraction of a second, or longer, like 1-2 seconds? does the sequence clicks-pause-clicks happen only once or for several cycles?