My 2011 ECO 6MT acted like yours. Would run ok, lose power, blow blue smoke. It would clear up and repeat. Used/burned lots of oil. Had my car towed to dealer. First the dealer advised blown turbo. Then determined two pistons cracked. Car was at dealer for 2 weeks. So - turbo, all 4 pistons and cylinder head replaced. When I picked up the car it seemed to run fine. Really did not want to keep the car with a rebuilt engine, so traded for my current car.Also want to note, that it does run good at times as well. It can run smooth for awhile then it goes back to jerking & then smooth & jerking & blue smoke.