I was driving home from work on Friday when I noticed that my 99 Accord was moving by itself. I was driving on the highway when I released the gas pedal so the car would slow down a little bit but it wasnt doing that. It was like the gas pedal was being pressed but it wasnt. I threw it in neutral and noticed it was reving up to a constant 4000 RPM.

I pulled into a rest stop and and shut the car off. I checked if the gas pedal was stuck and it wasnt. Each time I restarted the car it was idling at like 3500 RPM and wouldnt go down. I tried shutting it off and restarting and it would the same thing. I tried reving to more but that didnt work. Finally I noticed that everytime I tapped the gas pedal it would rev up a little and then drop the idle speed. I did that until it was idling at about 1200 RPM and got back onto the highway.

This car has never done anything like this before this incident and hasnt happened again. Can anyone explain what happened? Will this happen again? How do i fix it??

Thanks.