Could still be a problem with one of your applications. With my old pearl I had a problem similar to this due to the Facebook for Blackberry's application. It congested my email somehow and I stopped recieving emails. The phone was constantly trying to recover my emails causing it to run really slow and if I remember right it was causing a battery drain as well. I was then flooded with probably a few hundred emails over a couple hour period once I uninstalled the application. It's possible one of your applications is causing a similar problem.