I just recently drove my car across country. While driving on the interstate with cruise control set to 70mph the car would stumble sort of stall for a second and then would continue as normal. It would then happen again the same way but completely random. Then after a while the car began to rev up just a little bit but never changing gears. It would lurch slightly forward and then go back to normal once again. What is going one? I had fuel filter changed recently, oil change. Has gas in tank and drives pretty smooth