First thing I would do is check your spark plugs. Start at the #1 Cylinder. Pull the plug, look at it. If it looks fine, put it back and move to #2. and so on...
You are looking for a plug that looks different from the other three, or maybe 2 plugs that look different, and hopefully the plugs that look strange are paired (1,3 and 2,4). You are looking for either a grey ash deposit, that would indicate burning oil, or black carbon deposits that would indicate improper combustion.
If you only have 1 plug that is Black, check the plug, and wire. make sure it is snug. Clean it off with a wire brush, and make sure to blow it off before putting it back into the engine. See if that solves your problem.
If it is 2 plugs, and the 2 plugs are paired off the same coil, you might have a bad coil.
If you notice greyish ash deposits, that means you are burning oil, and oil is getting into the combustion chamber through leaky valve seals, or leaky rings. Your dealer should be able to do a compression test on each cylinder to determine this.
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Leave it to Random to Needlessly complicate things.