L4-2.0L Turbo,The car is not firing. There is oil on the plug number 4

I started my car last weekend and drove it. After, about 5 minutes, it started jerking very badly and it wasn't firing. There was no fault indication on the screen. I have run a diagnostic test and it didn't reveal anything. My mechanic checked the plugs and discovered that the plug number 4 is soaked in oil and that cylinder isn't firing.. The vehicle is still jerking and that plug is still oil soaked. Even when we replaced the plug, it still had the same problem.
My car has 18000 miles on the odometer.
My car has an automatic transmission.

My car has 18000 miles.
My car has