Hello

So recently I had to refill oil becuase I have an other problem with my car (there is a post about that, but briefly it uses 1L of oil for every 1 000km i drive)
After i refilled and refueled, the car jerks on every gear shift, and the RPM's hang at the point I shift and then suddenly drops fast. I am also not able to use "Cruise Control" when this happends.
Sometimes when I restart the car it's gone, and sometimes it's not.
But everytime I have this problem, the Cruise Control wont work (CC indicator on dash does not light)

As for the oil problem, it's not leaking, everything goes out the exhaust and it backfires like crazy. On cold starts alot of smoke. Im not sure but I think that might be related to either; Turbo, Piston Rings or the Valve Seals. (more details in my other post)

Cars specs: Volvo S60 2.0L 5 cyl Turbo 180hp (260k ish km - 2001 model - Manual)
"mods": nothing special, only lowered, Cold Air Intake, and one Muffler delete. (not realy mods, but thats what's been done to it other than weary parts)

Thanks for any replies

- Kola