I would define "acting up lately" first.
It freezes calls people on its own and pretty much doesn't want to respond.
Did you update to JB?
Did you do a FDR?
Did you check your settings? Some will reset after an FDR.
I had lots of things turn on that I had to turn off to achieve great battery life.
Did you update your apps?
Some combination of the above seems to fix a lot of problems for some of us.
Other people say trying these things don't help.