After spark plug/air filter/oil change power loss?

Hello community! Have a question about my ED9 again today… and that’s why I think that my ED9 has served a little bit of performance after a spark plug change (NGK V-Line 11), oil change (Shell Helix Super 10W40) and air filter change (touch air filter from Knecht/Mahle), which means a little bit of acceleration potential. Has anyone of you ever had such an experience? Furthermore, yesterday I showed my brother, who makes his driver’s license, how fast you can drive at most in the driving school in the traffic-relieved area (also called the Spielstraße) and then of course I drove in the first gear without giving gas, so almost 5-7 km/h. Only then I had to find out that my ED9 has started a little jerking during this slip, although we have driven a slightly downhill… what could this be?