What is the reason for the serious setback of the ninth generation Accord?

Hello, car owner According to your description, it should be caused by the frequent running of vehicles in urban areas, unclean engine throttle or carbon deposition at the air intake. I suggest you go to the repair shop to clean the carbon deposit on the throttle and air intake, and check whether the spark plug gap is too large. If the gap is too large, a new spark plug needs to be replaced. I hope my answer can help you and get your attention. Wish you a happy life and a happy family!