Hello I own a 2017 hyundia sonata. We purchased it with 44,000 must have been a rental. So now the issue. Seems to stall when let off brake or almost stalls, seems to idle ok but motor shakes. Changed plugs new oil is under warranty but already took it once to shop and no luck. seemed to drive better when ran Lucas in gas. Really don't want to go to dealership but have no choice, any thoughts???