i recently bought a s60 2,4t, the car i noticed was hesitating from take off and began to run sluggish when at a constant speed, kind of like going and then letting off and going and letting off. i changed the fuel filter and the spark plugs but it still has the same problems. any answers?

 

I would check the throttle body for carbon buildup. It can be cleaned easy enough. I know this one sounds simple, but check your air filter as well.

 

Do you have a CEL? If so check those codes and go from there. Also check real good for vacuum leaks.

 

ill check on the the throttle body, but @rspi, i am not throwing any codes at all, thats kinda the weird thing