Slight engine vibration on 2015 Aygo - how do I make the engine run cleaner?

Hi!

I decided to buy the Aygo I talked about in a previous post (2015 Aygo X-Play, X-Touch) and it drives great, everything works! Since I work at a Toyota dealership, I tend to drive the new and used Aygos around and I’ve noticed that many of the used aygos don’t feel as clean running as the new ones (used still being the new X-models).

What would be a good way to get the engine running just a bit smoother? There is no hesitaten and it drives perfectly fine, just feels a bit agricultural at times! Maybe an engine cleaning additive or a few tanks of Shell V-Power?

Thanks!