Kozmix

Hello everyone,
I'm having the following weird issue with my phone since a few months. Not sure how to troubleshoot it...

1.) Model Number ? Samsung Galaxy S Plus (GT-I9001)
2.) Firmware Version ? 2.3.6
3.) Baseband Version ? I9001XXKPL
4.) Kernel Version ? 2.6.35.7-perfdpi@DELL127 #1
5.) Build Number ? GINGERBREAD.XXKQE

Device is not rooted.

When not connected to a WLAN (so the 3G connection becomes active), my phone often forces itself to the home screen. When you're using an app, it closes it. When you're on another screen than the first one, it slides to the first. When the phone is on standby/locked, it lights up the display (showing the locking screen).

This behavior happens more while driving, but also when stationary at a remote location. This weird behavior typically appears to happen when the phone is transmitting data via its 3G connection. It never happens when connected via wifi. Even when disabling the GPS and GPS based apps (google latitude, waze, ...). I have already removed most of the installed apps, with no effect.

Any suggestions on what I can test further? Are there any logfiles I can access to see which app or process forces me into the homescreen all the time?

I've tried to give all relevant details to my knowledge. Feel free to ask further!

Thank you in advance!
Gunter