2001 Volvo S60 01 S60 code P0344 bearly runs

I just purchased this car and within minutes it had problems.I noticed a check engine light on so I scanned it and it said p0344 cam sensor circut intermittent. Well not long after it shut off. It was running fine before even with this code.I was just sitting in the car running fine and then it just shut off. So far I have check all vac lines replaced vvt actulator and still nothing. It will start (very hard after many cranks) then what it will do is surge rapidly, with a chug, chug, chug out the exhaust and a small amount of black smoke.I clear out the code and it come back instantly.I also now that`s it won`t run right decided to do so maintinance. Plugs, fuel, air.
im stummped. Don`t want to become a parts changer. If and when it starts I can get it to rev fine if over 1500 rpm but when I let go of the throttle it starts to chug and will most of the time stall. Help !