Wawa:
Did you try putting the device in standby with software?$PMTK161,0*28
Leo..
You can, but the standby current is circa 1mA and there appears to be a bug.
If you power it down (with $PMTK161,0*28) as soon as you get a valid fix, which you might supose is the normal thing to do and you do this for say 30 minutes.
The GPS can then get stuck in that when it powers up again, it can take a very long time to get fix again, 30 or 40 minutes.
I did not investigate further but I suspect the way out of the problem migh be to cold restart the GPS when it gets stuck, takes longer than say 60 seconds to get a fix.
The Ublox GPSs have an equivalent command, but that puts the GPS in backup mode, the current then is circa 8uA.