2017 Hyundai Elantra Engine Shaking Issue

Описание: Once in a while this vehicle at idling or at slowing down starts to fluctuate rpm and then it vibrates the entire car. No check engine light. For a while, it vibrates more as you accelerate and gives chill that car will die.
My mechanic cleaned throttle body and replaced spark plugs. Yet it still does it.
I don’t know what to do now?