I have a 2007 S40 - only 10K miles. I haven't had any problems with the car up until now. In fact, I love the car. I just got back from a two week vacation & the car had trouble starting. When I finally got it to start it just kept stalling & the service engine light is on. I can get it to start & to run, but when I floor the gas pedal, it just barely goes. Any idea what is wrong?

 

turbo or non turbo?

 

When my 2000 S40 acted in a similar fashion, about three years ago, it was the ignition coils. They were replaced and the problem was solved.
That was the problem with my car anyway, can't say yours is the same issue.