Data Logging Stops After Losing GPS Signal

JMP91:
do you think this will cause problems with printing a new value to the SD card every iteration of the main Arduino loop?

Well, how about something like

void loop() {
  boolean isUpdated = false;
  
  if (gps.location.isUpdated()) {
    [...]
    isUpdated = true;
  }
  
  if (gps.speed.isUpdated()) }
    [...]
    isUpdated = true;
  }
  
  [...]
  
  if (isUpdated) {
    // Write to SD card here
  }
}

Hope this helps,

Brad
KF7FER