Well I have serious problem with the GPS when flashing other ROM than the LG stock. I have tried lots of ROMs like CM11 nightlies, vanir, carbon and none of them have working GPS. I have downloaded GPS Status apps and they give me no fix. With stock rom I have fix within 10-15 secs even the first time. The problem is described here
I suppose that it has to do with google services and the gapps pack I flash (the banks one) but I can't find a solution.