Ye this is an odd one I noticed when I first got my n900, In another thread someone was having problems whereby there phone in 2g/3g would get a really bad 3g signal... It seems though that if you force ti to 3g only the phone gets brilliant 3g signal?! I think this is n900 issue not autodisconnect...

@Calvin for some reason when I manually check my emails or use internet radio my autodisconnect doesn't seem to connect, in emails it shows it trying to sync but cant, same for radio...