This right here. Irl flying im constantly listening to the harmonics of the engine. The day before my ppl checkride as my instructor and I were climbing out, we hit around 1700ft for 3000 to go do one more round of practice maneuvers. I noticed the engine seemed off and remember looking at the tac and noticing no issues. Somewhere around 2000 feet all of a sudden the engine sputtered and rolled back to about 1900 rpm for a few seconds and then normalized. I remember saying well ok, I think we’re good on maneuvers, and we headed back to the field. Turns out a bad spark plug wire caused the issue.
I will say after that I had no issues with nerves for the checkride lol which I passed the following day.