Says its the Crankshaft Position Sensor Failure on Bank 1 and Bank 2. I ordered new sensors and had them installed and the p0300 code cleared but the p0021 code came back.

My car is softly rocking side to side and at times has a ruff start by seeming like it doesn't want to. Well that only happened twice. I only had the car for a month so what else needs to be checked to solve this code?