Everyone...... Just to update everyone here! I am running 4.3.1 on my phone! I'm jailbroken but had horrible battery drain after updating. After following some other people's talk about going to the restrictions settings under general and turning off ping and the other unnecessary apps it helped a little! This is what cured everything! Go to settings/ then go down to store/ then click your email/ then turn it off! It cured my drain!!!!!! Try it and see what happens!