Whats causing this? Vehicle shutters when you slowly roll into the throttle to accelerate at speeds above 45 mph. Engine light flashes but does not stay on. Not saving any codes.

I can repeat the shutter when cruising in overdrive
and the vehicle begins to climb a long rolling hill.
Just before the transmission would downshift to a
lower gear to maintain the speed the engine
begins to shutter or jerk. This can be avoided by
giving the throttle a little punch to cause the
transmission to downshift into a lower gear while
climbing the incline before the transmission
downshift on its own.
Took it to the dealer and they were unable to get
the shutter to happen. They suspect it is a misfire.
I didn't think a misfire could be initiated by
creating a load on the engine.