My 2000 S40 starting revving/accelerating without using the gas pedal. Had to keep the brake firmly down to keep from going through a stop sign.
What would cause this? It scared my wife, where she will not even ride in the car.

Any ideas?

thanks,

 

I would firstly check the throtle wire for any broken branches and after that I would check the throtle sensor for any dirty contacts or similar electrical mulfunction. I know the solution sounds simple for such a serious problem but I guess it is better to start from the simple staff. Good luck

 

Did you replace your spark plugs recently? I had the same accelerating problem. Reading through these forums, and reading the topic 'spark plugs' everyone recommended copper core spark plugs. i was sold Champion Double Platinum plugs at the store originally and then when i switched to NGK copper core plugs the problem went away.