Ok, I know Im a bit late with this reply, but maybe I can help someone else having this issue. I had same issue, I have optimus f6. I selected this phone knowing that it had only about 1.5 gig of internal memory, thinking I will just throw a 32 gig micro SD card in it and call it a day. THINK AGAIN!! I ended up rooting the phone, not an easy task, as LG and T-mobile have went out of there way to make rooting this phone a nightmare. Then once rooted, still could not use any of the bootleg apps to move apps to the SD Card. WTF? Its my phone I should be able to do with it as I please. Long story short, I had my brother in law (IT guy) look at it, he figured out a way to make the phone think that the mico sd card was the internal memory, fixing my storage nightmare.
If you like apps, dont buy this phone, unless you are good with hacking these devices!