When I turned off the engine the car started the electronic vibrate?

Hello, last month when I parked the car, I shifted gear from D to P and P to D and D to P then I turned off the engine. When I turned off the engine the car started the electronic vibrate. When I felt the vibrate on my driving seat, I started the engine (after five seconds vibrating). And then the car started the slight to moderate vibrating on the driving wheel and cabin but now it is not an electronic vibrating it is mechanical vibrating when the gear N and P. It happens the engine turn on but stopped times for example red lights. Also, it happens when the engine is cold or hot. After I go 1,000 miles, but it happens. I went to service they lifted the car and oiled a metal pedal under the car (they said it puts the engine). But nothing changes also might be increase. I want to learn what the problem with my car?