Phone loses all connection activity at random when I turned on mobile data!

[jack kwan]

Hi, my lg g2 works perfectly fine until recently. It drops all connections/signals from time to time when my mobile data is on, even bluetooth connection/signal. It's really strange, because I connect my bluetooth to my car,and at times, the bluetooth signal disconnects with the 4g and phone signal. But if i turn off my mobile data, then my bluetooth and my calling signal rarely shuts off. Any idea?? Thanks.