On the way back from visiting some friends the other day, my car starting reving on its own out of no where! I was in neutral the whole time it was reving. It was steady reving not pump reving. It started on its own at about 1000 rpms then gradually went up all the way to 3500 rpms. I pulled over and checked some vacuum lines but didn't see anything out of place. So I turned the car off then on but it started up again, only this time it didn't rev so high, it was back down to about 1500. So I drove home and after taking it through fifth, it calmed down and was back to normal at 500 rpms at idle. I took it out today, everything was smooth until about half an hour into the ride and it started up again!! Oh yea, its not the recent clip for the cruise control, I had that done to see if that solved the problem but it didn't. So its gotta be something else. I don't know what's wrong. Can anyone help??? Has this happened to anyone else???? Any and all info would be greatly appreciated!!