Today I was on the highway I had it in cruise control at 2100 RPM's, then the RPM started going up and then came back down to 2100 RPM's. The car did not rev and no other needles were going crazy. I thought it was maybe the cruise control so I turned it off but it kept happening. Even when I was at the traffic light it was doing it. I want to know what it could be and what can be done to fix it. Please help, when it comes to wiring, electronics, I have no idea on what to do or what can cause this.