Iv put this problem on here before but last time it was more vague. The problem is my iPhone 3GS shuts of randomly then won't turn on until I plug it in to a power outlet. Last time I thought it may have been a mobile substrate problem but there are new developments. It reset in safe mode a few times meaning it is not a mobile substrate problem. Iv discovered it only shuts off when it uses Internet. 3G or wifi. Once in a while it shuts off while sending a txt but the majority of the time is while I'm using safari or Facebook. If I do not use Internet it is ok. Last night I took an hour car ride too and from Bristol it was a total of 2 hours and I listened to music the whole time but did not respond to facebook or use safari and it was ok. So I'm pretty sure it's involving Internet. Has Anyone els has had this problem? Also I would have put this in the jailbreak thread but I can't find it on the everythingicafe app.