i-Phone 16gig 3Gs auto off etc etc..

Unit: i-Phone 16gig 3Gs

Problem: Auto-OFF, suddenly off when playing games, auto restart, when off cannot be on unless you insert a cable and press power on, off when tap at the back, etc etc...
Action taken: Restore, update, jailbreak ( thetered), same problem.

Solution: Change Battery! The CULPRIT! Original battery installed assembled in CHINA!

Replaced by a non-original battery from CHINA also. (watta heck!) but at least work at its best, been used for 5 hours now! No hassle yet, working good so far!