Why does my van hesitate when diving 40 t0 50 mph?

Is the check engine light on?

Engines will almost ALWAYS hesitate when cruising at 40-50mph when going up a slight incline WITH cruise control on. On my 2011 Mazda CX-9 AWD Touring, it does the same thing. So did my 2002 Toyota Camry back in the day. The issue is normal. The cruise control senses the car is slowing down and tries to compensate, however the tranny is at the optimal gear change threshold, so what is really going on, is your tranny is trying to shift. This is why you will not see this occur going up a steep incline. To compensate for this, on my Mazda, I simply just put it in manual mode for the time being, until I am done climbing that slight incline. Again, very normal.