CucamongaPrius

I have a 05’ with 157000 miles. As I accelerate, the car starts moving in electric mode until it reaches 14 mph. Then I noticed the engine starts up and at a low acceleration the feels like it is slipping. But if I press on the accelerator harder it speeds up fine. It is only jerky when press the accelerator slightly. The check engine light lit up once and turn off quickly Has anybody had this happen to you? And what was the cause.