General :: Why Won't Phone Boot And Stay Booted

I have a six month old Epic 4G, rooted, CWM recovery,. I used Root Uninstaller to remove three of the annoying preloaded apps that I never use. Otherwise, my phone is stock. I'm still on the 2nd to last Gingerbread update, as the one that arrived in late Jan won't apply to my rooted phone. I doubt my problem is specific to the device, though, which is why I'm posting here. I have a 32GB SD connected to the phone.

The problem: I have a very irritating "warm reboot:"

1) After booting, the phone is sometimes (not always) extremely laggy. When I use a system monitor to see what is taking the CPU, it appears to be "System" that is taking all the CPU. If the phone is not obviously laggy when starting up, this problem does not occur.
2) The flash card scans always say they complete. It never reboots before these complete.
3) Although the flash scans have completed, it takes quite a while for all of my app icons to load, suggesting it is still going through the SD card.
4) Within a few minutes after booting, the screen goes black and the four soft keys light up. If the screen is already off when this happens, the screen first turns on briefly, and then goes black!
5) About five to fifteen seconds later, the GUI restarts and it starts scanning the flash.

What else I notice:

* The "uptime" reported is not reset, which tells me there was no actual "reboot."

* Once I can get it to boot without doing this, it's stable for days.

* Using the phone right after it boots seems to increase the chance of this happening, but it's hard to say.

* In the past, if I disabled WiFi and 4G and then went into airplane mode, this would greatly reduce the chance of this happening, but now my phone has been constantly warm rebooting even in airplane mode. The phone appears to be getting less stable with time.

* This does not appear to be correlated with phone temperature. The phone can be cool to the touch or warm to the touch and this will happen.

* I've tried wiping all the various caches before. Makes no difference.

Questions:

1) Is this a known issue that is not present in a 3rd party ROM?

2) Does moving a lot of apps to SD cause this? With only 1/2 GB of built-in app memory, I have no choice but to move almost everything to the SD.

3) Does having a LOT of files on the SD card cause this? I have many nandroid backups on the SD.

4) Is there a real name for this "reboot" that I can Google for? When I search for "reboot loop" or "warm reboot" I get unrelated failures. I saw one thread where someone mentioned a "sense reboot" but that seems to be an HTC thing?

5) If I clear off the SD card, or somehow signal that most directories are not to be scanned, will this make a difference?

6) How can I figure out what is going on, why the phone is restarting the UI? Does Android have a boot-up problem of being at 100% CPU for a few minutes that automatically causes a UI reset? As I said, once the phone boots without doing this warm boot, it will be stable for days.