iPhone 3G with "no service" when 3G is on

[desmondojose]

My iPhone 3G this morning isn't working when I have 3G turned on. I've talked to other people with iPhone's in my area that have 3G just fine. When 3G is on it goes from full signal strength and edge to 1 bar and no e or gprs, to searching to nothing, and keeps cycling. I did a restore to my jailbroken 3.1, didn't work, did a restore to official 3.1 didn't fix it, reset all settings on phone still didn't fix it, but if I turn on 3G I get full strength with Edge, anyone run across this or know what to do?
thanks,

[Cowboy]

I would go to att and get a new sim if that doesnt fix it take it to apple because that would be there problem