Sonata Nine Premium Edition1.6?just started in the morning. What's the problem?

When the cold car starts, the idle speed will be high for a while, because the on-board computer will increase the idle speed for 3 to 5 minutes to make the car start smoothly, because the car will shake a little after the idle speed is high, which is normal. If you are talking about the jitter after the idle speed returns to normal, it may be caused by the dirty throttle. You can check the throttle. If it is too dirty, you need to step on the accelerator.