No results from tightening screws for me, they're already tight. However, pulling the battery did work this time, for some reason. I used to be able to use the GPS without all the google stuff (framework services, play services, play store) running on my phone, but while I was on vacation recently I needed to set "high accuracy" to get it to work at all. That requires google play services, which requires google framework services, and so on. After pulling the battery, "GPS only" mode is working again, so that's good. The GPS Test app has been helpful, but didn't help while I was on vacation, I tried several of the GPS Test and Support apps in the play store, not much help there.
Anyways, the countdown goes on, only about 2 months now until Verizon allows me to upgrade my phone. My iPad GPS always works, never any problems with it, so I'll be looking at the iPhone 6 (for other reasons as well *smile*). The timing is just too fortuitous not to, and no more Samsung for me.