I'm having trouble getting my GPS to be accurate on my iPhone 4 when I run. I've used both Runkeeper and MapMyRun and both add extra distance to my run (looks like I'm running in zig zags down my path). I've tried turning off the wifi, doing a hard reset, and resetting the networking preferences. None of that has helped. Before I run, I open Google Maps and wait until there is not circle around the blue dot. Google Maps is very accurate. I then make sure the GPS signal is good/strong in the running app before I start, but none of that has helped. My low tier Android phone worked much better (when it wasn't freezing up) for running. Any ideas?