Hello everyone, i have problems with my car mercedes b200 2009 right now. I bought it from December ( 5k CAD, 163k km ) , its pretty good at the first month , i can drive on the highway, i have no problems with the car. When it come to the third month, thing got stress, the car seems to be old , so the part from the car was worn out , i have to replace the bearing in the front on the drive side, gas cap , the shock behind was crack so i have to replace it and it cost me around 2k CAD with the labors fees.

Recently, my car have a crankshaft sensor problem, and code P0411 . My car cant drive over 90 km ( when ever i try to hit 100km for the highway speed, the car always jerking or something i dont know how to explain it, it like when you drive on many speed bumps )

i dont know what happend, i try to replace the bearing cause it cause the car shaking when driving on highway, i try to replace the crankshaft But nothing change much, the crankshaft position sensor code still on , and the car still jerk when i hit 90km,  The engine difficult to start. Sometime when i slow down the car, it turn off and not run at all, i look at the screen and it said oil pressure something, i cant see it clearly and very few time its showing me ( it only appear for 2,3 seconds ). 

 i really dont know what to do now with the car. should i sell it or keep it ? anyone have same experience please help me .