2011 Honda Accord drivetrain & axles problems

As I was completing a left hand turn, I applied pressure to the brake and my car began to accelerate despite my foot being firmly applied to the brake. I continued to maintain pressure to the brake yet the car continued to accelerate where I hit an embankment / tree, I steered the car back onto the road and turned off the ignition. I contacted honda though was given a report indicating that there weren't any diagnostic codes & the honda factory engineer drove the car 5 to 6 miles without acceleration issues.

Wife was driving at highway speed when car began to violently shake as if engine was misfiring. Check engine light came on, then severely reduced power. She was barely able to exit and make it across the access road and into a turn lane with the accelerator to the floor. Car still shook violently as she placed it in park. Dealership cannot explain shaking. Car only has 4,700 miles and was purchased new from servicing dealer. They said oil was 1.5-2 quarts low so they topped it off.