So I've had the Check Engine light on for the past few days. (2002 S60 AWD) The car chugs every so often and generally runs crappy sometimes. Also it does not seem to have the zip that it used to when I got it about a year ago. Almost feels like a transmission problem, but after bringing it in and having it checked at Auto Zone and they said that it looks like it is a bad Turbo Boost Sensor. They unfortunately didn't have that part available.

1. Can anyone tell me the best place (other than the dealers) to get a new one?
2. Can anyone tell me where this part can be found on my car/how to replace it?
3. Does anyone have a picture of what it looks like?
4. Has anyone else had this problem and what fixed it?

Also, something worth mentioning is when I first got it, I changed oil to full synthetic, it was fine for a week, then started leaving oil spots in my garage, oil leaks stopped, came back, and then has been gone now for several months. And when I let the car idle, it will be fine for a couple minutes and then it will start to plume up smoke.

Thanks!