Cannot get the service department to understand that this issue with driving the vehicle at 60 miles per our on interstate 77 when another car passes and need to slow the vehicle down. Scary part is that when the engine goes down to 40 miles per hour the rpm goes up to 3 and takes 2 pumps to the gas pedal to bring the rpm down to 2 and then the car accelerates back up to 60 miles. This takes 25 seconds and I am praying that no one behind me slams into to me. The part that is most frustrating is it does not repeat itself each day only randomly so I cannot show the service tech what is going on. Also, it is frustrating that they cannot mount this car onto a computer to see if the transmission is out of tune; dealership has no such machine to diagnose this engine issue. Cannot wait till lease is up; not buying car; just praying each day that I do not end up dead on the road.