For those who are still having the data problem issue, your best and quickest bet is to do the following:
1. Dial *228 and let MetroPCS program your phone.
**Note** My guess is that the merge between T-Mobile and Metro made Metro make some changes to how they connect to 4G; an update, I assume, is wirelessly pushed to phones that are not on a custom ROM or to phones that have the MetroPCSHiddenMenu.apk file. I know I keep bringing this little APK up, but I do think Metro uses this APK to change the settings of the phones.
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I did lose connection on my phone, but after dialing *228, it came back and it is working perfectly fine. If you are unable to update your phone using *228, try putting the MetroPCSHiddenMenu.apk back in "system/app" where it originally is supposed to be.
Good luck.