2016 dodge grand caravan

Hello all I recently bought a 2016 dodge grand caravan and my problem us the vehicle will surge between 80 and 90 kms/hr. It seems to do it more once the vehicle is warm. The tach will jump up and down. If you hit the gas or let off the problem goes away and may or may not come back right away...

We replaced key fob batteries 3 months ago and they now don't work at all with brand new batteries. Is there a receiving unit on the van itself that has a replacement battery available?? Would an add-on remote keyless entry kit solve this problem?? Thanks