Display of Pokémon comes with a delay

Whenever I'm playing Pokémon Go, I cant seem to find any Pokémon. It seems to be because of some delay. I often can only catch Pokémon when I'm standing still and wait for the Pokémon to show up (if there are any).

When I'm walking with friends, they find many Pokémon, but I need to wait for roughly 2 minutes before the same Pokémon show up on my map.

When I minimize the Pokémon app by pressing the 'Recent apps button' and push the Pokémon tab, it will (I think) re-establish the app and the Pokémon will show up.

It looks like my Samsung S6 does not collect data all the time for the game, but only after some minutes. I think that's the reason why I need to wait for Pokémon to show up.

I have the same ISP as my friends and same phone.

Does anyone have any solution for me?

On August 1st you would have been experiencing slowness from an API change Niantic made to begin preventing access from external sites.

There was a significant delay for any communication involving GPS, which includes Pokemon appearing in your field of view.

After Niantic fully blocked everything a couple days ago, you should be seeing significantly improved performance....although a severe lack of any means to track the Pokemon nearby :(