mobile

Hello.
this problem has been going on for a few months but I never really tried to fix it until a couple of days ago.
This is exactly what happens: I start my phone and try to get a GPS fix with any apps, as long as I don't have a 3G connection, it works flawlessly.
the moment I enable the 3G connection, the GPS fix is lost and never works again until I reboot. wifi, 2g, airplane mode, they all give me a perfect GPS fix. as soon as the little "H+" shows on the screen, the GPS dies until the next reboot.
the weirdest thing about it is that it happens with every single room I try. so far I've tried CM 12, 11 and 10. exact same problem
Tried PA4.5 and 4.6, again, the exact same thing.
I even tried going back to stock, first to 4.3, nothing.
right now I'm on stock 4.0.4 which is the oldest image I could find, flashed everything back to stock (except boot-loader and recovery)
I've wiped everything between each room flash, of course.
I'm running out of ideas here. any help would be very appreciated :)