I bought a used 2012 Corolla LE. Every now and then, it accelerates rather harshly - no other good way to describe it. Sometimes, at freeway speeds, the engine does not feel smooth even at steady speeds. I discovered that the car had had a fender-bender, which damaged the black plastic 'grill'-like part attached behind the bottom of the front bumper. Could this have caused any damage that makes the engine accelerate/run harshly?