My 2012 Mini Cooper RMP dips very slightly when idling or stopped.

What is your question?

So I have this problem that when my Mini is idling or stopped at a light the RPM's will dip ever so slightly. There is no signs of stalling or chugging, but I get this little putter like symptom. It doesn't always happen, but it is pretty constant. If you are stopped it might happening every 15-20 seconds. A little back story is that I have all 4 spark plugs and fuel injectors replaced a few months back and that actually rectified a more noticeable problem. This seems to be like the last little bit of my problem. If you use a code reader I get no issues, I have no dash lights on, absolutely nothing indicating a problem. But I can tell its just not perfect. Not far off, but not exactly perfect. My question is where do I start lol .. I've seen a couple mechanics and I have gotten no answers and I would love to fix it, but no clue where to start. Hoping you all might have some suggestions I could start with myself and conduct a little testing. Really any advise is appreciated. TY

What makes this problem better or worse?

neither

How long has your 2012 Mini Cooper had this problem?

6 months