Greetings! I searched this forum for a similar issue, but I don't think any of them compare to what I was experiencing. Sorry for the long post, I am writing this in case anyone has a similar problem, and hopefully this solution will work for you. My X recently (within the last week) started having extremely poor battery performance under the same usage conditions as the previous week (K-9 syncs every 15 min, maybe 2 texts per hour, 2-3 emails per hour, maybe 5 total minutes of phone use). After 4 hours, the battery would be at 20-30% To make matters worse, most functions were extremely slow to respond (contact loading, test message loading, recent calls, bookmarks, any scrolling was choppy, etc.) The delay when trying the most basic things (opening the browser, making a call) was getting unbearable. I started backtracking the changes in the last week. Although I started tinkering with Google's App Inventor over three weeks ago, that's where I focused. I uninstalled all App Inventor programs, including the Eyes-Free Text to Speech engine. This engine was recommended by Google to do things like read text messages in the Apps you create. Still no luck. I decided to investigate the battery use a little more. In Battery Manager, I found that "Android System" was using about 70% of my battery. I was typically used to seeing things like "display" at the top. I have an app called Android System Info. This showed my CPU usage pegged at 100% (even after a reboot). It never got lower than 99%. The biggest CPU hog was "Android System" at 75-80%, consistently. This App has a tab to view the log, and I noticed several recurring error messages in the log. They were occurring at the rate of about 180 times per second! The error? "Invalid TTS Engine" Well, the TTS is controlled by the "Android System". The "Android System" was constantly trying to load the uninstalled TTS engine. I went into "Settings...Voice input and output", and, although the Eyes Free TTS engine wasn't available, the default TTS was not set. I checked the box to have the native TTS as the default, and checked the box for "Always use my settings". Everything immediately went back to normal. CPU usage is now around 10-20%, and "Display" is back at the top of my battery hogging functions. Battery life is back to over 10 hours, and the delays are gone.