I have a 2013 Hyundai Elantra. It is knocking

What is your question?

When I am driving straight, no matter the speed, every 3-4 minutes it starts knocking with a little bit of vibration. From inside the car, it sounds like a helicopter in the distance. It usually last for about 20 seconds. Then it will repeat itselfevery 3-4 minutes.

What makes this problem better or worse?

nothing

How long has your 2013 Hyundai Elantra had this problem?

3 days