It started this morning when i was getting on the e-way.I got to about 70 mph when I hit the gas my rpm started going up and down wouldnt go any faster i had to let off the gas then it worked fine.I was on my way home going about 35 mph it started doing it again my rpm were going up and down till the car shut off i coasted to my road shut the car off waited a minute started back up it worked but seems to be running not the same any suggestions

Does it feel like the transmission is shifting up and down? Or does it seem like a fuel delivery problem?