Problems with mobile data. Lumia 820

[Paul L820]

I have been getting problems with 3G data. Not one app ( that requires internet connection) works fine when in 3G but then 4G comes up and it starts working good. I've got everything set to default, could this be a problem with the phone or does it have to be a problem with my carrier?

 

[Harrie-S]

Difficult to say for sure.
Could you swap your SIM with a friend to see what happens?
Or use below app to check the speed of your 3G and 4G.Speedtest.net | Windows Phone Apps+Games Store (United States)
This should give you a good indication where the problem is.

 

[James Anderson16]

To mind this problem is not possible to overcome and but, there may some hardware issue that creating such issue.