P0300 is a misfire code, P0301 and P0302 are misfire present in cylinder's number 1 and 2. A misfire is incomplete combustion usually caused by loss of fuel or spark. For example a bad spark plug wire, coil failure spark plugs, fuel injector or vacuum leak. The cylinders seen as having a problem ion your car are the two cylinders nearest the driver's side of the engine. When two cylinders adjacent to each other show a problem look for a vacuum hose off (that could affect two adjacent cylinders) or there is a possibility of a blown head gasket on those two adjacent cylinders. I hope it turns out to be a minor problem but get it checked out sooner or more damage could occur.