I would go into the form and download a different Radio and try that out. It could be that ROM also. Mighty ROMs are usaully really good and I hardly have any issues with them myself but I am using a different one right now and I would suggest trying a different version of ROM if you dont want to attempt the Radio fix.
This should help fix the problem. It not the phone may have an issue and you may want to get the phone tested. I would flash it back to a Stock ROM and take it to a Sprint Service Center to allow them to test it.
I hope this helps.