2000 S40 Engine Revs to High RPMs on Its Own

[dw7037]

Recently purchased a 2000 S40, so I'm not familiar with the service history. Here are the issues I'm experiencing with it:

- Cranks a lot before starting (acts like it doesn't want to start, but eventually it does). It has done this since we bought it, but it's a used car, so we weren't expecting anything perfect.

- Yesterday, the engine has started revving to high RPMs even when I'm not touching the gas pedal. For example, after having trouble starting, when it finally did start (and while still in Park), the engine revved to 5000 RPMs. It was scary. I couldn't even shift out of Park because the car would have jolted.

- While driving, the car accelerates on its own - like I'm pressing on the gas pedal, but I'm not. I've had to be extremely cautious following behind other cars for fear of the car suddenly accelerating on its own and running into something.

What could be the problem?? And how much am I looking at to repair it?

[Livens]

The hard start is most likely the fuel pressure regulator. And when these go out fuel is getting sucked into the intake manifold through the vacuum line that is attached to the FPR. I'm not sure if the two problems could be related... but having alot of unmetered fuel being sucked into the intake could cause the engine to rev.

Easy to check the FPR, just pull the vacuum line off of it and check for fuel in it. A FPR will run you about $140 from a dealer (just the part, not installation). When I was replacing mine I looked high and low on the internet and could not find a price much better.

[difflock54]

Check and clean the throttle body as well as previously suggested above.

[Jeff__graham]

I had the same problem and replaced the throttle position sensor and idle air control valve, but problem still persisted. Finally replaced the temp sensor and haven't had any further issues.

[jcartermedia]

Had the same thing on my 2000 V40 when I first bought it. Ended up being the temp sensor malfunctioning.