I have a 2001 s40 that has numerous problems. So far I've replaced the cat, the turbo, head gasket, and thermostat. It seems to be running rich with little power, and idles rough sometimes stalling. The car overheats after a few minutes of driving and the temp gauge is normal then shoots right up. The cat gets super hot quickly, so thats what makes me think its dumping fuel into the engine, this thing is a nightmare and its just been sitting for a few months because I just don't have the time. Has anyone run into this combination of issues?

 

I realize it's been awhile since you posted. Can you give more information? Did this just all of a sudden happen or did something else happen first? How many miles on the car? Has the water pump been replaced? etc.