Hey Buddah. I don't think that cache will improve game speed: in a year, it has only saved 2.5MB in my phone. A better option would be uninstalling and reinstalling (as long as you remember your e-mail and password).
If the problem continues, I would consider closing all apps before launching the game. If this doesn't solve your problem, it might be because of the GPS location, which makes the game connection laggy in some devices. Just disable this.
If none of these worked, maybe it's because of your device, but you shouldn't have problems as long as it's less than 4-5 years old (depends on if it is a low-end one or not).