I have a 2001 S40 that I get the #2 coil code. I swapped coils and still the same thing. I also swapped the wires, put in new plugs and still the same thing. When this happens the DSA light and check engine lights come on. After resetting the codes it will run fine for a few minutes and then it does what it does.

 

what codes are you seeing? I assume there's some misfires since you started looking at spark. Have you measured fuel pressure? try this - on the driver's side of the fuel rail is the fuel pressure regulator. There's a small S-shaped vacuum line. Pop that off - if fuel drips out, you need to replace the FPR. After that, try measuring fuel pressure (should be some vids on Youtube for the how to). Next is to check for intake air leaks - vacuum lines, boost tubes etc. Spray around with carb cleaner etc and consider a smoke test.