Very slight "rubber band in drive train" sensation

Lately I have been noticing a very slight sensation when driving our 2007 like there is a rubber band in the drive train. The closest analogy I can make is what happens when a manual transmission car is left in 4th gear and the speed falls down to 15 mph or so and it starts bucking. But tone it down about 100x, so it is just a slight pulsing vibration and it lasts for no more than a second. It happens sometimes when accelerating from a full stop, and other times when the accelerator is pressed down following a coast to lower speeds (as in when timing arrival at a stop light). In both of these cases the ICE is starting up. I don't recall it ever happening when easing up on the pedal or maintaining even pressure. There are no odd noises.

My best guess is that something is very slightly off on the motor and what I'm feeling is the flex plate compensating. No CEL, and I have not yet checked for codes which would not set the light. If I plug in the mini-VCI cable and fire up Techstream, where should I look for evidence of a problem? Fuel trim? Anything else?

Or maybe a bad motor mount?

I'm not going to rule out the possibility that it always did this and I'm just obsessing about it now, so noticing it more.

Thanks.