Enable 4G LTE On Nexus 4 For Select Carriers

Step 1: Go the the dialer on your Nexus 4
Step 2: Enter this code to get to Phone info

*#*#4636#*#*

Step 3: In Set preferred network type, change the selection to “LTE/GSM/CDMA auto (PRL)”
That’s it. You will lose signal for a moment, after which it will reconnect to the 4G LTE band.