Wii LEGO games framedrop

[Raidmaon]

Hello! I have my wii for almost 2 years now. I got it from a relative in Spain and he got it from a second hand. I really love the wii and I really love LEGO Videogames. It is a modded Wii and I'm playing the games on wiiflow with an SD card. I recently started playing LEGO LOTR on the wii but sometimes the frame drops. I can't say that the framedrop is massive, but I don't know if it's normal, because I watched some playthroughs of this version and I don't see that problem. This also happens to every lego game I play. Screenshots from the previous owner date back to 2013 if the age is a factor. And since I got it I never cleaned it inside.
I want to know if it is normal and if it's not I want to know a way to fix it.

 

[Tzy]

The same thing happens to me too, there are fps drops in some parts, it doesn't only happen to me in lego games, in no more heroes and others too. It's not normal and I still don't know how to fix it